HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) CME Test (opens in a new window) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Murphey, M. D. Articles by Gajewski, D. A. Search for Related Content PubMed PubMed Citation Articles by Murphey, M. D. Articles by Gajewski, D. A. Related Collections Musculoskeletal Radiology Oncologic Imaging

From the Archives of the AFIP

Imaging of Synovial Sarcoma with Radiologic-Pathologic Correlation¹

¹ From the Departments of Radiologic Pathology (M.D.M., M.S.G., B.T.J.) and Soft Tissue Pathology (J.F.S.), Armed Forces Institute of Pathology, 6825 16th St NW, Building 54, Room M-133A, Washington, DC 20306; Department of Radiology and Nuclear Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md (M.D.M.); Department of Radiology, National Naval Medical Center, Bethesda, Md (M.S.G.); Department of Radiology, Hospital Universitario Miguel Servet, Zaragoza, Spain (A.M.C.R.); and Departments of Radiology (M.D.M.) and Orthopedic Surgery (D.A.G.), Walter Reed Army Medical Center, Washington, DC. Received May 2, 2006; revision requested May 19 and; received June 9; accepted June 9. All authors have no financial relationships to disclose. Address correspondence to M.D.M. (e-mail: murphey{at}afip.osd.mil).

	Abstract

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

 
Synovial sarcoma is the fourth most common type of soft-tissue sarcoma, accounting for 2.5%–10.5% of all primary soft-tissue malignancies worldwide. Synovial sarcoma most often affects the extremities (80%–95% of cases), particularly the knee in the popliteal fossa, of adolescents and young adults (15–40 years of age). Despite its name, the lesion does not commonly arise in an intraarticular location but usually occurs near joints. Histologic subtypes include monophasic, biphasic, and poorly differentiated; the cytogenetic aberration of the t(X;18) translocation is highly specific for synovial sarcoma. Although radiographic features of these tumors are not pathognomonic, findings of a soft-tissue mass, particularly if calcified (30%), near but not in a joint of a young patient, are very suggestive of the diagnosis. Cross-sectional imaging features are vital for staging tumor extent and planning surgical resection; they also frequently reveal suggestive appearances of multilobulation and marked heterogeneity (creating the "triple sign") with hemorrhage, fluid levels, and septa (creating the "bowl of grapes" sign). Two features associated with synovial sarcoma that may lead to an initial mistaken diagnosis of a benign indolent process are slow growth (average time to diagnosis, 2–4 years) and small size (< 5 cm at initial presentation); in addition, these lesions may demonstrate well-defined margins and homogeneous appearance on cross-sectional images. Synovial sarcoma is an intermediate- to high-grade lesion, and, despite initial aggressive wide surgical resection, local recurrence and metastatic disease are common and prognosis is guarded. Understanding and recognizing the spectrum of appearances of synovial sarcoma, which reflect the underlying pathologic characteristics, improve radiologic assessment and are important for optimal patient management.

	LEARNING OBJECTIVES FOR TEST 6

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

 
After reading this article and taking the test, the reader will be able to:

• Describe the radiologic manifestations of synovial sarcoma.
  
• Recognize the pathologic basis of the radiologic features of synovial sarcoma.
  
• Discuss the pathologic spectrum of synovial sarcoma as well as the treatment options and prognosis.
  

	Introduction

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

 
Synovial sarcoma was first reported in 1893 and represents a relatively common type of primary soft-tissue malignancy (1–5). Synovial sarcoma accounts for 2.5%–10.5% of all primary malignant soft-tissue neoplasms (6–13). Previous terminology for this lesion includes tendosynovial sarcoma, synovial cell sarcoma, synovioma, synovial endothelioma, malignant synovioma, and synovioblastic sarcoma (2,4). Despite this nomenclature, these lesions do not arise in an intra-articular location but usually occur near joints. Synovial sarcomas typically affect adolescents and young adults. The extremities, particularly the knee in the popliteal fossa, are most frequently affected. Synovial sarcoma is an intermediate- to high-grade neoplasm with extensive metastatic potential.

Because of the aggressive potential behavior of synovial sarcoma, pathologic and radiologic assessment is important for staging and evaluating lesion extent to direct appropriate therapy. Imaging findings, although not pathognomonic, frequently suggest the diagnosis. Radiographic findings of a soft-tissue mass near but not in a joint in a young patient (15–40 years old), particularly if calcification is present, are very suggestive of synovial sarcoma. Cross-sectional imaging appearances often seen with synovial sarcoma include multilobulated morphology and marked heterogeneity (creating the "triple sign") with hemorrhage, fluid levels, and septa (creating the "bowl of grapes" sign). In this article, the clinical features, pathologic characteristics, spectrum of radiologic appearances, and treatment and prognosis of synovial sarcoma are discussed and illustrated.

	Clinical Characteristics

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

 
Synovial sarcoma is the fourth most common soft-tissue sarcoma in the material from the Armed Forces Institute of Pathology (AFIP), following malignant fibrous histiocytoma (currently known as undifferentiated high-grade pleomorphic sarcoma), liposarcoma, and rhabdomyosarcoma (1–10). In the United States, the prevalence of synovial sarcoma ranges from 2.5% to 10% of all soft-tissue sarcomas as reported by several institutions (6–10). Similar rates have been reported in population-based studies from Japan (8.3%) (11), Sweden (7%) (12), and France (10.5%) (13).

Synovial sarcoma occurs most frequently in adolescents and young adults, with the majority of patients presenting at 15–40 years of age (2,9). In the study by Cadman et al (8), 84% of patients with synovial sarcoma were 10–50 years old. The median age at presentation in several recent large series ranged from 30 to 38 years (13–18). However, as with most neoplastic processes, there is a broad age range and cases have been reported in newborns and the elderly (6,19). In the pediatric population, synovial sarcoma is the most common nonrhabdomyosarcomatous soft-tissue sarcoma (20). A mild male predominance (1.2:1 ratio) has been described by some authors (15). In contradistinction, other reports have indicated a slight female predominance (13,17). In the largest single group reported, a series of 672 cases seen in consultation over a 10-year period at the AFIP, there was no significant difference in gender distribution (9). No race or ethnic predilection has been reported.

Patients with synovial sarcoma usually present with a palpable soft-tissue mass or swelling (6,8). These lesions are often slow growing initially. Duration of symptoms before diagnosis varies widely, from weeks to decades (8); however, the average duration of symptoms is 2–4 years (2). There are reported cases with as long as a 20-year history of symptoms. The long duration of symptoms and initial slow growth of synovial sarcomas may simulate those of or give a false impression of a benign process. This unusual manifestation is important to recognize, because diagnosis may be significantly delayed otherwise. Pain and tenderness at the site of the mass are frequent, and some patients present with pain but no palpable mass (8). This symptom is unusual compared with other soft-tissue sarcomas that typically manifest as painless masses. Symptoms of sensory and motor dysfunction distal to the lesion, caused by primary or secondary involvement of adjacent nerves, have been reported (8). Weight loss and constitutional symptoms are unusual, but when present usually indicate a poorly differentiated tumor (2). Although synovial sarcoma has occasionally been cited in association with trauma in the literature (2), most cases with this history are likely coincidental. Local trauma may cause hemorrhage in a soft-tissue mass or may bring the mass to the attention of the patient or examining physician.

The majority of synovial sarcomas (80%–95%) occur in the extremities (Fig 1). The lower extremity is most often affected, accounting for 60%–71% of cases, whereas 16%–25% occur in the upper limb (8,9,15,16,18) (Fig 2). The single most frequent site of involvement is the popliteal fossa of the knee (8,9,15,16,18). Synovial sarcoma is the most common malignancy of the deep soft tissues of the foot and ankle in patients 6–45 years of age and the most common malignancy of the lower extremity in patients 6–35 years of age (9). In the AFIP series, 18% of all synovial sarcomas occurred in the foot and ankle. Other less commonly affected sites include the head and neck (5% of cases); trunk, thorax, and chest wall (7%; Fig 3); retroperitoneum (0.3%); and pelvis (8%) (8,9,15,16,21–23). However, synovial sarcoma has also been reported in almost all anatomic locations, with rare involvement of the skin, viscera (kidney, lung, prostate, esophagus, heart), central nervous system, pleura, peripheral nerve, and bone (2–5,21–23). Despite its name, synovial sarcoma infrequently (estimated 5%–10% of cases) originates within a joint (8,14) (Fig 4). The majority of tumors occur either adjacent to (40%–50% of cases) or within 5 cm of (60%–75%) a joint (24). In the study by Jones and colleagues (25), 63% of lesions were within 7 cm of a joint. When intraarticular involvement does occur, it is more commonly because the juxtaarticular neoplasm extended into the joint rather than the tumor arose there (Fig 5).

View larger version (91K): [in this window] [in a new window] [Download PPT slide]   Figure 1a.  Synovial sarcoma with an intermuscular origin adjacent to the hip of an 18-year-old man who noticed an enlarging soft-tissue mass. (a, b) Axial T1-weighted (a, repetition time msec/echo time msec = 690/25) and T2-weighted (b, 2301/95) magnetic resonance (MR) images show a large juxtaarticular heterogeneous soft-tissue mass (M) with signal intensity slightly higher than that of muscle with T1 weighting and intermediate signal intensity with T2 weighting. The lesion is centered between the rectus (arrow), tensor fascia lata (T), and sartorius (S) muscles, which are displaced. A small amount of intermuscular fat is seen posteriorly (arrowhead). (c) Photograph of the axially sectioned gross specimen reveals similar features with a septated, multilobulated soft-tissue mass (*) arising between the rectus (arrow), tenor fascia lata (T), and sartorius (S) muscles.

View larger version (88K): [in this window] [in a new window] [Download PPT slide]   Figure 1b.  Synovial sarcoma with an intermuscular origin adjacent to the hip of an 18-year-old man who noticed an enlarging soft-tissue mass. (a, b) Axial T1-weighted (a, repetition time msec/echo time msec = 690/25) and T2-weighted (b, 2301/95) magnetic resonance (MR) images show a large juxtaarticular heterogeneous soft-tissue mass (M) with signal intensity slightly higher than that of muscle with T1 weighting and intermediate signal intensity with T2 weighting. The lesion is centered between the rectus (arrow), tensor fascia lata (T), and sartorius (S) muscles, which are displaced. A small amount of intermuscular fat is seen posteriorly (arrowhead). (c) Photograph of the axially sectioned gross specimen reveals similar features with a septated, multilobulated soft-tissue mass (*) arising between the rectus (arrow), tenor fascia lata (T), and sartorius (S) muscles.

View larger version (135K): [in this window] [in a new window] [Download PPT slide]   Figure 1c.  Synovial sarcoma with an intermuscular origin adjacent to the hip of an 18-year-old man who noticed an enlarging soft-tissue mass. (a, b) Axial T1-weighted (a, repetition time msec/echo time msec = 690/25) and T2-weighted (b, 2301/95) magnetic resonance (MR) images show a large juxtaarticular heterogeneous soft-tissue mass (M) with signal intensity slightly higher than that of muscle with T1 weighting and intermediate signal intensity with T2 weighting. The lesion is centered between the rectus (arrow), tensor fascia lata (T), and sartorius (S) muscles, which are displaced. A small amount of intermuscular fat is seen posteriorly (arrowhead). (c) Photograph of the axially sectioned gross specimen reveals similar features with a septated, multilobulated soft-tissue mass (*) arising between the rectus (arrow), tenor fascia lata (T), and sartorius (S) muscles.

View larger version (47K): [in this window] [in a new window] [Download PPT slide]   Figure 2a.  Synovial sarcoma near the elbow in a 15-year-old boy who had a small mass there for 9 years that recently rapidly increased in size. (a) Anteroposterior radiograph of the forearm shows a soft-tissue mass (arrowhead) below the elbow with a small focus of amorphous calcification superiorly (large arrow) and extrinsic erosion of the adjacent radius (small arrow). (b, c) Coronal T1-weighted (630/20) (b) and axial T2-weighted (2339/90) (c) MR images reveal the soft-tissue mass (*) with intermediate signal intensity on the short TR image and intermediate to high signal intensity on the long TR image. Low-signal-intensity focus (arrowheads in b) represents the calcification, which is better seen on the radiograph. Extrinsic erosion of the radius is seen on the axial MR image (arrow in c). (d) Photograph of the coronally sectioned gross specimen shows the synovial sarcoma with hemorrhage (H) and focus of calcification (between arrowheads).

View larger version (80K): [in this window] [in a new window] [Download PPT slide]   Figure 2b.  Synovial sarcoma near the elbow in a 15-year-old boy who had a small mass there for 9 years that recently rapidly increased in size. (a) Anteroposterior radiograph of the forearm shows a soft-tissue mass (arrowhead) below the elbow with a small focus of amorphous calcification superiorly (large arrow) and extrinsic erosion of the adjacent radius (small arrow). (b, c) Coronal T1-weighted (630/20) (b) and axial T2-weighted (2339/90) (c) MR images reveal the soft-tissue mass (*) with intermediate signal intensity on the short TR image and intermediate to high signal intensity on the long TR image. Low-signal-intensity focus (arrowheads in b) represents the calcification, which is better seen on the radiograph. Extrinsic erosion of the radius is seen on the axial MR image (arrow in c). (d) Photograph of the coronally sectioned gross specimen shows the synovial sarcoma with hemorrhage (H) and focus of calcification (between arrowheads).

View larger version (148K): [in this window] [in a new window] [Download PPT slide]   Figure 2c.  Synovial sarcoma near the elbow in a 15-year-old boy who had a small mass there for 9 years that recently rapidly increased in size. (a) Anteroposterior radiograph of the forearm shows a soft-tissue mass (arrowhead) below the elbow with a small focus of amorphous calcification superiorly (large arrow) and extrinsic erosion of the adjacent radius (small arrow). (b, c) Coronal T1-weighted (630/20) (b) and axial T2-weighted (2339/90) (c) MR images reveal the soft-tissue mass (*) with intermediate signal intensity on the short TR image and intermediate to high signal intensity on the long TR image. Low-signal-intensity focus (arrowheads in b) represents the calcification, which is better seen on the radiograph. Extrinsic erosion of the radius is seen on the axial MR image (arrow in c). (d) Photograph of the coronally sectioned gross specimen shows the synovial sarcoma with hemorrhage (H) and focus of calcification (between arrowheads).

View larger version (144K): [in this window] [in a new window] [Download PPT slide]   Figure 2d.  Synovial sarcoma near the elbow in a 15-year-old boy who had a small mass there for 9 years that recently rapidly increased in size. (a) Anteroposterior radiograph of the forearm shows a soft-tissue mass (arrowhead) below the elbow with a small focus of amorphous calcification superiorly (large arrow) and extrinsic erosion of the adjacent radius (small arrow). (b, c) Coronal T1-weighted (630/20) (b) and axial T2-weighted (2339/90) (c) MR images reveal the soft-tissue mass (*) with intermediate signal intensity on the short TR image and intermediate to high signal intensity on the long TR image. Low-signal-intensity focus (arrowheads in b) represents the calcification, which is better seen on the radiograph. Extrinsic erosion of the radius is seen on the axial MR image (arrow in c). (d) Photograph of the coronally sectioned gross specimen shows the synovial sarcoma with hemorrhage (H) and focus of calcification (between arrowheads).

View larger version (75K): [in this window] [in a new window] [Download PPT slide]   Figure 3a.  Synovial sarcoma of the posterior chest wall in a 31-year-old man with a nontender, progressively enlarging, soft-tissue mass. (a) Axial postcontrast computed tomographic (CT) scan shows a large posterior chest wall mass with low attenuation centrally (*) resulting from necrosis and a thick nodular wall peripherally (arrows). (b) Photograph of the axially sectioned gross specimen reveals similar features, with necrosis (N) centrally and a thick nodular wall of viable tumor (T) peripherally.

View larger version (80K): [in this window] [in a new window] [Download PPT slide]   Figure 3b.  Synovial sarcoma of the posterior chest wall in a 31-year-old man with a nontender, progressively enlarging, soft-tissue mass. (a) Axial postcontrast computed tomographic (CT) scan shows a large posterior chest wall mass with low attenuation centrally (*) resulting from necrosis and a thick nodular wall peripherally (arrows). (b) Photograph of the axially sectioned gross specimen reveals similar features, with necrosis (N) centrally and a thick nodular wall of viable tumor (T) peripherally.

View larger version (155K): [in this window] [in a new window] [Download PPT slide]   Figure 4a.  Synovial sarcoma arising in the knee joint of a 10-year-old girl who developed progressive pain, swelling, and flexion contracture over 2 years after mild trauma. (a) Sagittal short inversion time inversion recovery (STIR) (5000/26/160) MR image shows a large high-signal-intensity soft-tissue mass that appears to originate in the Hoffa fat pad (*) with invasion throughout the joint and the distal femoral (F) and proximal tibial (T) epiphyses. (b) Photograph of the sagittally sectioned gross specimen reveals the intraarticular mass (straight arrows) with hemorrhage (H) and invasion of the distal femoral (arrowhead) and proximal tibial (curved arrow) epiphyses.

View larger version (113K): [in this window] [in a new window] [Download PPT slide]   Figure 4b.  Synovial sarcoma arising in the knee joint of a 10-year-old girl who developed progressive pain, swelling, and flexion contracture over 2 years after mild trauma. (a) Sagittal short inversion time inversion recovery (STIR) (5000/26/160) MR image shows a large high-signal-intensity soft-tissue mass that appears to originate in the Hoffa fat pad (*) with invasion throughout the joint and the distal femoral (F) and proximal tibial (T) epiphyses. (b) Photograph of the sagittally sectioned gross specimen reveals the intraarticular mass (straight arrows) with hemorrhage (H) and invasion of the distal femoral (arrowhead) and proximal tibial (curved arrow) epiphyses.

View larger version (171K): [in this window] [in a new window] [Download PPT slide]   Figure 5a.  Synovial sarcoma with secondary joint invasion. (a) Sagittal proton-density-weighted (2450/38.5) MR image of the knee shows a large popliteal soft-tissue mass (*) with invasion of the knee joint, as evidenced by tumor (arrows) surrounding the posterior cruciate ligament (P). The patient, a 47-year-old man with a 2-year history of progressive limitation of joint movement, also had invasion of the femur (arrowheads). (b) Photograph of a sagittally sectioned, whole-mounted specimen (hematoxylineosin [H-E] stain) from a 35-year-old man reveals invasion of the anterior recess of the ankle by a soft-tissue mass (*), which originates adjacent to the joint (arrow). The intraarticular component of the lesion also causes extrinsic erosion of the anterior tibial cortex (arrowhead). The patient presented with clinical symptoms of limited foot dorsiflexion.

View larger version (84K): [in this window] [in a new window] [Download PPT slide]   Figure 5b.  Synovial sarcoma with secondary joint invasion. (a) Sagittal proton-density-weighted (2450/38.5) MR image of the knee shows a large popliteal soft-tissue mass (*) with invasion of the knee joint, as evidenced by tumor (arrows) surrounding the posterior cruciate ligament (P). The patient, a 47-year-old man with a 2-year history of progressive limitation of joint movement, also had invasion of the femur (arrowheads). (b) Photograph of a sagittally sectioned, whole-mounted specimen (hematoxylineosin [H-E] stain) from a 35-year-old man reveals invasion of the anterior recess of the ankle by a soft-tissue mass (*), which originates adjacent to the joint (arrow). The intraarticular component of the lesion also causes extrinsic erosion of the anterior tibial cortex (arrowhead). The patient presented with clinical symptoms of limited foot dorsiflexion.

	Pathologic Features

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

There are three main histologic subtypes of synovial sarcoma: biphasic, monophasic, and poorly differentiated (28) (Fig 6). Biphasic synovial sarcoma represents 20%–30% of lesions and has both a mesenchymal spindle cell component and an obvious epithelial component as seen at light microscopy (Fig 6a). The epithelial cells usually form glands, but they may also be seen as solid sheets, nests, cords, and papillary structures, and they may show squamous metaplasia. The glandular component may predominate and occasionally obscure the spindle cell elements, an appearance suggestive of adenocarcinoma and that has been referred to as the purely glandular type monophasic synovial sarcoma.

View larger version (162K): [in this window] [in a new window] [Download PPT slide]   Figure 6a.  Photomicrographs of various histologic types of synovial sarcoma. (a) Biphasic synovial sarcoma (original magnification, x250; H-E stain) has a blue spindle cell mesenchymal component (arrow) and pinker glandular elements (arrowheads). (b) Monophasic synovial sarcoma (original magnification, x200; inset magnification, x400; H-E stain) typically appears with fascicles and sheets of uniform oval cells but without a glandular component. Inset shows scattered mast cells (arrowheads). (c) Monophasic synovial sarcoma with positive keratin stain (original magnification, x300; Kermix stain) shows the brown staining (arrowheads) in individual tumor cells. (d) Poorly differentiated synovial sarcoma (original magnification, x250; H-E stain) has an epithelioid growth pattern and relatively uniform round cells, a characteristic that makes differentiation from other small round blue cell tumors (eg, Ewing sarcoma) difficult without immunohistochemical staining.

View larger version (160K): [in this window] [in a new window] [Download PPT slide]   Figure 6b.  Photomicrographs of various histologic types of synovial sarcoma. (a) Biphasic synovial sarcoma (original magnification, x250; H-E stain) has a blue spindle cell mesenchymal component (arrow) and pinker glandular elements (arrowheads). (b) Monophasic synovial sarcoma (original magnification, x200; inset magnification, x400; H-E stain) typically appears with fascicles and sheets of uniform oval cells but without a glandular component. Inset shows scattered mast cells (arrowheads). (c) Monophasic synovial sarcoma with positive keratin stain (original magnification, x300; Kermix stain) shows the brown staining (arrowheads) in individual tumor cells. (d) Poorly differentiated synovial sarcoma (original magnification, x250; H-E stain) has an epithelioid growth pattern and relatively uniform round cells, a characteristic that makes differentiation from other small round blue cell tumors (eg, Ewing sarcoma) difficult without immunohistochemical staining.

View larger version (95K): [in this window] [in a new window] [Download PPT slide]   Figure 6c.  Photomicrographs of various histologic types of synovial sarcoma. (a) Biphasic synovial sarcoma (original magnification, x250; H-E stain) has a blue spindle cell mesenchymal component (arrow) and pinker glandular elements (arrowheads). (b) Monophasic synovial sarcoma (original magnification, x200; inset magnification, x400; H-E stain) typically appears with fascicles and sheets of uniform oval cells but without a glandular component. Inset shows scattered mast cells (arrowheads). (c) Monophasic synovial sarcoma with positive keratin stain (original magnification, x300; Kermix stain) shows the brown staining (arrowheads) in individual tumor cells. (d) Poorly differentiated synovial sarcoma (original magnification, x250; H-E stain) has an epithelioid growth pattern and relatively uniform round cells, a characteristic that makes differentiation from other small round blue cell tumors (eg, Ewing sarcoma) difficult without immunohistochemical staining.

View larger version (131K): [in this window] [in a new window] [Download PPT slide]   Figure 6d.  Photomicrographs of various histologic types of synovial sarcoma. (a) Biphasic synovial sarcoma (original magnification, x250; H-E stain) has a blue spindle cell mesenchymal component (arrow) and pinker glandular elements (arrowheads). (b) Monophasic synovial sarcoma (original magnification, x200; inset magnification, x400; H-E stain) typically appears with fascicles and sheets of uniform oval cells but without a glandular component. Inset shows scattered mast cells (arrowheads). (c) Monophasic synovial sarcoma with positive keratin stain (original magnification, x300; Kermix stain) shows the brown staining (arrowheads) in individual tumor cells. (d) Poorly differentiated synovial sarcoma (original magnification, x250; H-E stain) has an epithelioid growth pattern and relatively uniform round cells, a characteristic that makes differentiation from other small round blue cell tumors (eg, Ewing sarcoma) difficult without immunohistochemical staining.

Poorly differentiated synovial sarcomas are generally epithelioid in morphology and have high mitotic activity (usually > 15–20/10 high-power field) with geographic necrosis (18,31–33) (Fig 6d). This subtype represents up to 15%–25% of all synovial sarcomas. A very distinctive low-power microscopic pattern for poorly differentiated synovial sarcoma is perivascular tissue sparing, in which rings of tumor form around vessels, with large areas of adjacent geographic necrosis. Poorly differentiated synovial sarcomas can be confused with round cell tumors, such as Ewing sarcoma, although differentiation can be accomplished with immunohistochemical staining and molecular methods.

Grading of synovial sarcoma is achieved by applying the highly reproducible, widely accepted grading scheme for all sarcomas, the FNCLCC (French Federation Nationale des Centres de Lutte Contre le Cancer) scheme, which uses a combined score from three separate parameters, including degree of differentiation, mitotic activity, and necrosis (34,35). Both biphasic and monophasic synovial sarcomas are usually intermediate grade (grade 2/3); however, both types can be high grade (grade 3/3). Poorly differentiated synovial sarcomas are high-grade tumors.

The presence of keratin (epithelial marker) positivity (approximately 90% of cases), measured with immunohistochemical staining in correlation with the histologic appearance, is diagnostic for synovial sarcoma (37,38) (Fig 6c). Both the glandular component (diffusely) and the spindle cell component (focally) demonstrate single cells (monophasic and poorly differentiated subtypes) or clusters of cells (biphasic subtype) that are positive for epithelial markers, most notably pankeratins, EMA, and CK7. CK7 is generally absent from malignant peripheral nerve sheath tumor (as well as pankeratins in this tumor) and Ewing sarcoma, and this finding can aid in diagnosis of synovial sarcoma (39). CD99, which is found as a cytoplasmic membrane marker in Ewing and primitive neuroectodermal tumors, can also be positive in synovial sarcoma (62% of cases). CD34, which is diffusely positive in hemangiopericytoma and solitary fibrous tumor, is negative in synovial sarcoma. Epithelial-type and neural-type cadherins can be found in biphasic synovial sarcoma and to a lesser degree in monophasic and poorly differentiated synovial sarcoma, but they may be useful, in combination with other markers, to separate biphasic synovial sarcoma from mesotheliomas or other tumors (40).

Cytogenetic studies can be performed on formalin-fixed paraffin embedded tissues. The hallmarks for synovial sarcoma are the t(X;18) translocation and SYT-SSX gene fusion products, which can be identified by using FISH (fluorescence in situ hybridization) or RT-PCR (reverse transcription polymerase chain reaction) studies, respectively. This genetic aberration has been identified in greater than 90% of synovial sarcomas and is highly specific, since it has not been identified to date in any other tumors, to the best of our knowledge. Molecular testing is usually performed when there is very little tissue, when the immunohistochemical stains are not diagnostic for synovial sarcoma, or when the tumor is poorly differentiated and mimics Ewing sarcoma. Several variations of the t(X;18) translocation leading to two different gene fusions have been described and associated with the vast majority of synovial sarcomas. These are the SYT-SSX1 and SYT-SSX2 types that account for 67% and 33% of gene fusions, respectively (2–5,42,43). Although much controversy exists in the literature, there is no definite prognostic difference between these two gene fusion types (41). However, biphasic tumors are generally SSX1, and monophasic tumors are either SSX1 or SSX2 (42).

The pathologic differential diagnosis for synovial sarcoma includes the following: carcinosarcoma; other biphasic tumors of the gynecologic tract; teratoma; mixed tumor; malignant mesothelioma; fibrosarcoma; solitary fibrous tumor or hemangiopericytoma; cellular schwannoma; leiomyosarcoma; malignant peripheral nerve sheath tumor (36); Ewing sarcoma or primitive neuroectodermal tumor; and other small round cell tumors, depending on whether biphasic, monophasic, or poorly differentiated. These lesions can all be distinguished by the specific morphologic features of synovial sarcoma (such as stromal collagen, scattered mast cells, and bland cytology of ovoid tumor cells in fascicles; soft tissue or specific organ location; patient age; and immunohistochemical findings of EMA, keratins, and CK7) and particularly by molecular methods in difficult cases or those with scant material.

	Imaging Features

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

 
Radiographs appear normal in approximately 50% of cases of synovial sarcoma, particularly those with small lesions (1,43). Larger legions that are deeply seated or that occur in areas of complex anatomy such as the pelvis may also be occult at radiography. Synovial sarcomas detected at radiography typically appear as nonspecific, round to oval juxtaarticular soft-tissue masses. Calcification is identified in up to 30% of synovial sarcomas at radiography (1, 43) (Figs 2, 7).

View larger version (118K): [in this window] [in a new window] [Download PPT slide]   Figure 7a.  Largely cystic synovial sarcoma in the popliteal region in a 12-year-old boy with a painless soft-tissue mass first noted 4 years ago. (a) Lateral radiograph shows soft-tissue fullness in the popliteal fossa (*) with a small, nonspecific calcification superiorly (arrow). (b–d) Axial T1-weighted (b, 700/16), sagittal T1-weighted fat suppressed postcontrast (c, 800/20), and coronal STIR (d, 2550/30/150) MR images reveal a largely cystic, popliteal soft-tissue mass (C) with a focal nodular area of solid tissue anteriorly (arrowheads). The lesion is intermuscular as demonstrated by the surrounding fat (split fat sign) (arrows). The cystic component (C) demonstrates thin peripheral enhancement and is low signal intensity with T1 weighting (b) and very high signal intensity with the STIR sequence (d), an appearance simulating that of a ganglion or popliteal cyst. However, the solid component (S) reveals diffuse enhancement and is higher signal intensity with T1 weighting (b) and lower signal intensity with the STIR sequence (d). (e) Transverse sonogram of the solid component shows a heterogeneous intermediate echogenicity, ovoid soft-tissue mass. Note the foci of increased echogenicity (arrows), which correspond to calcifications on the radiographs. (f) Photograph of the sectioned gross specimen reveals the solid component (S) and smooth walls of the collapsed cyst cavity (*), corresponding to the imaging findings.

 

View larger version (133K): [in this window] [in a new window] [Download PPT slide]   Figure 7b.  Largely cystic synovial sarcoma in the popliteal region in a 12-year-old boy with a painless soft-tissue mass first noted 4 years ago. (a) Lateral radiograph shows soft-tissue fullness in the popliteal fossa (*) with a small, nonspecific calcification superiorly (arrow). (b–d) Axial T1-weighted (b, 700/16), sagittal T1-weighted fat suppressed postcontrast (c, 800/20), and coronal STIR (d, 2550/30/150) MR images reveal a largely cystic, popliteal soft-tissue mass (C) with a focal nodular area of solid tissue anteriorly (arrowheads). The lesion is intermuscular as demonstrated by the surrounding fat (split fat sign) (arrows). The cystic component (C) demonstrates thin peripheral enhancement and is low signal intensity with T1 weighting (b) and very high signal intensity with the STIR sequence (d), an appearance simulating that of a ganglion or popliteal cyst. However, the solid component (S) reveals diffuse enhancement and is higher signal intensity with T1 weighting (b) and lower signal intensity with the STIR sequence (d). (e) Transverse sonogram of the solid component shows a heterogeneous intermediate echogenicity, ovoid soft-tissue mass. Note the foci of increased echogenicity (arrows), which correspond to calcifications on the radiographs. (f) Photograph of the sectioned gross specimen reveals the solid component (S) and smooth walls of the collapsed cyst cavity (*), corresponding to the imaging findings.

 

View larger version (130K): [in this window] [in a new window] [Download PPT slide]   Figure 7c.  Largely cystic synovial sarcoma in the popliteal region in a 12-year-old boy with a painless soft-tissue mass first noted 4 years ago. (a) Lateral radiograph shows soft-tissue fullness in the popliteal fossa (*) with a small, nonspecific calcification superiorly (arrow). (b–d) Axial T1-weighted (b, 700/16), sagittal T1-weighted fat suppressed postcontrast (c, 800/20), and coronal STIR (d, 2550/30/150) MR images reveal a largely cystic, popliteal soft-tissue mass (C) with a focal nodular area of solid tissue anteriorly (arrowheads). The lesion is intermuscular as demonstrated by the surrounding fat (split fat sign) (arrows). The cystic component (C) demonstrates thin peripheral enhancement and is low signal intensity with T1 weighting (b) and very high signal intensity with the STIR sequence (d), an appearance simulating that of a ganglion or popliteal cyst. However, the solid component (S) reveals diffuse enhancement and is higher signal intensity with T1 weighting (b) and lower signal intensity with the STIR sequence (d). (e) Transverse sonogram of the solid component shows a heterogeneous intermediate echogenicity, ovoid soft-tissue mass. Note the foci of increased echogenicity (arrows), which correspond to calcifications on the radiographs. (f) Photograph of the sectioned gross specimen reveals the solid component (S) and smooth walls of the collapsed cyst cavity (*), corresponding to the imaging findings.

 

View larger version (91K): [in this window] [in a new window] [Download PPT slide]   Figure 7d.  Largely cystic synovial sarcoma in the popliteal region in a 12-year-old boy with a painless soft-tissue mass first noted 4 years ago. (a) Lateral radiograph shows soft-tissue fullness in the popliteal fossa (*) with a small, nonspecific calcification superiorly (arrow). (b–d) Axial T1-weighted (b, 700/16), sagittal T1-weighted fat suppressed postcontrast (c, 800/20), and coronal STIR (d, 2550/30/150) MR images reveal a largely cystic, popliteal soft-tissue mass (C) with a focal nodular area of solid tissue anteriorly (arrowheads). The lesion is intermuscular as demonstrated by the surrounding fat (split fat sign) (arrows). The cystic component (C) demonstrates thin peripheral enhancement and is low signal intensity with T1 weighting (b) and very high signal intensity with the STIR sequence (d), an appearance simulating that of a ganglion or popliteal cyst. However, the solid component (S) reveals diffuse enhancement and is higher signal intensity with T1 weighting (b) and lower signal intensity with the STIR sequence (d). (e) Transverse sonogram of the solid component shows a heterogeneous intermediate echogenicity, ovoid soft-tissue mass. Note the foci of increased echogenicity (arrows), which correspond to calcifications on the radiographs. (f) Photograph of the sectioned gross specimen reveals the solid component (S) and smooth walls of the collapsed cyst cavity (*), corresponding to the imaging findings.

 

View larger version (163K): [in this window] [in a new window] [Download PPT slide]   Figure 7e.  Largely cystic synovial sarcoma in the popliteal region in a 12-year-old boy with a painless soft-tissue mass first noted 4 years ago. (a) Lateral radiograph shows soft-tissue fullness in the popliteal fossa (*) with a small, nonspecific calcification superiorly (arrow). (b–d) Axial T1-weighted (b, 700/16), sagittal T1-weighted fat suppressed postcontrast (c, 800/20), and coronal STIR (d, 2550/30/150) MR images reveal a largely cystic, popliteal soft-tissue mass (C) with a focal nodular area of solid tissue anteriorly (arrowheads). The lesion is intermuscular as demonstrated by the surrounding fat (split fat sign) (arrows). The cystic component (C) demonstrates thin peripheral enhancement and is low signal intensity with T1 weighting (b) and very high signal intensity with the STIR sequence (d), an appearance simulating that of a ganglion or popliteal cyst. However, the solid component (S) reveals diffuse enhancement and is higher signal intensity with T1 weighting (b) and lower signal intensity with the STIR sequence (d). (e) Transverse sonogram of the solid component shows a heterogeneous intermediate echogenicity, ovoid soft-tissue mass. Note the foci of increased echogenicity (arrows), which correspond to calcifications on the radiographs. (f) Photograph of the sectioned gross specimen reveals the solid component (S) and smooth walls of the collapsed cyst cavity (*), corresponding to the imaging findings.

 

View larger version (85K): [in this window] [in a new window] [Download PPT slide]   Figure 7f.  Largely cystic synovial sarcoma in the popliteal region in a 12-year-old boy with a painless soft-tissue mass first noted 4 years ago. (a) Lateral radiograph shows soft-tissue fullness in the popliteal fossa (*) with a small, nonspecific calcification superiorly (arrow). (b–d) Axial T1-weighted (b, 700/16), sagittal T1-weighted fat suppressed postcontrast (c, 800/20), and coronal STIR (d, 2550/30/150) MR images reveal a largely cystic, popliteal soft-tissue mass (C) with a focal nodular area of solid tissue anteriorly (arrowheads). The lesion is intermuscular as demonstrated by the surrounding fat (split fat sign) (arrows). The cystic component (C) demonstrates thin peripheral enhancement and is low signal intensity with T1 weighting (b) and very high signal intensity with the STIR sequence (d), an appearance simulating that of a ganglion or popliteal cyst. However, the solid component (S) reveals diffuse enhancement and is higher signal intensity with T1 weighting (b) and lower signal intensity with the STIR sequence (d). (e) Transverse sonogram of the solid component shows a heterogeneous intermediate echogenicity, ovoid soft-tissue mass. Note the foci of increased echogenicity (arrows), which correspond to calcifications on the radiographs. (f) Photograph of the sectioned gross specimen reveals the solid component (S) and smooth walls of the collapsed cyst cavity (*), corresponding to the imaging findings.

 

View larger version (92K): [in this window] [in a new window] [Download PPT slide]   Figure 8a.  Extensively calcified synovial sarcoma in a 36-year-old woman who presented with a mass anterior to the elbow that had progressively enlarged over 15 months, resulting in a flexion deformity. (a) Lateral elbow radiograph shows a large calcified soft-tissue mass (arrows) anterior to the elbow without evidence of an effusion. (b) Axial CT scan also reveals the extensively calcified soft-tissue mass (arrows). (c, d) Coronal oblique T1-weighted (650/36) (c) and sagittal gradient-echo (1000/13/30°) (d) MR images demonstrate the large heterogeneous soft-tissue mass (arrowheads) with low- to intermediate-signal-intensity areas (*) corresponding to the calcifications seen on radiographs and CT scans. The extent of low to intermediate signal intensity is not as prominent as might be expected from the radiographic or CT appearance, likely related to intermixture with viable tumor cells. The mass is anterior to the anterior recess of the elbow, and lack of joint effusion is consistent with juxtaarticular but not intraarticular origin. (e) Photograph of the coronally sectioned gross specimen shows extensive calcification (*) superiorly.

View larger version (64K): [in this window] [in a new window] [Download PPT slide]   Figure 8b.  Extensively calcified synovial sarcoma in a 36-year-old woman who presented with a mass anterior to the elbow that had progressively enlarged over 15 months, resulting in a flexion deformity. (a) Lateral elbow radiograph shows a large calcified soft-tissue mass (arrows) anterior to the elbow without evidence of an effusion. (b) Axial CT scan also reveals the extensively calcified soft-tissue mass (arrows). (c, d) Coronal oblique T1-weighted (650/36) (c) and sagittal gradient-echo (1000/13/30°) (d) MR images demonstrate the large heterogeneous soft-tissue mass (arrowheads) with low- to intermediate-signal-intensity areas (*) corresponding to the calcifications seen on radiographs and CT scans. The extent of low to intermediate signal intensity is not as prominent as might be expected from the radiographic or CT appearance, likely related to intermixture with viable tumor cells. The mass is anterior to the anterior recess of the elbow, and lack of joint effusion is consistent with juxtaarticular but not intraarticular origin. (e) Photograph of the coronally sectioned gross specimen shows extensive calcification (*) superiorly.

View larger version (128K): [in this window] [in a new window] [Download PPT slide]   Figure 8c.  Extensively calcified synovial sarcoma in a 36-year-old woman who presented with a mass anterior to the elbow that had progressively enlarged over 15 months, resulting in a flexion deformity. (a) Lateral elbow radiograph shows a large calcified soft-tissue mass (arrows) anterior to the elbow without evidence of an effusion. (b) Axial CT scan also reveals the extensively calcified soft-tissue mass (arrows). (c, d) Coronal oblique T1-weighted (650/36) (c) and sagittal gradient-echo (1000/13/30°) (d) MR images demonstrate the large heterogeneous soft-tissue mass (arrowheads) with low- to intermediate-signal-intensity areas (*) corresponding to the calcifications seen on radiographs and CT scans. The extent of low to intermediate signal intensity is not as prominent as might be expected from the radiographic or CT appearance, likely related to intermixture with viable tumor cells. The mass is anterior to the anterior recess of the elbow, and lack of joint effusion is consistent with juxtaarticular but not intraarticular origin. (e) Photograph of the coronally sectioned gross specimen shows extensive calcification (*) superiorly.

View larger version (145K): [in this window] [in a new window] [Download PPT slide]   Figure 8d.  Extensively calcified synovial sarcoma in a 36-year-old woman who presented with a mass anterior to the elbow that had progressively enlarged over 15 months, resulting in a flexion deformity. (a) Lateral elbow radiograph shows a large calcified soft-tissue mass (arrows) anterior to the elbow without evidence of an effusion. (b) Axial CT scan also reveals the extensively calcified soft-tissue mass (arrows). (c, d) Coronal oblique T1-weighted (650/36) (c) and sagittal gradient-echo (1000/13/30°) (d) MR images demonstrate the large heterogeneous soft-tissue mass (arrowheads) with low- to intermediate-signal-intensity areas (*) corresponding to the calcifications seen on radiographs and CT scans. The extent of low to intermediate signal intensity is not as prominent as might be expected from the radiographic or CT appearance, likely related to intermixture with viable tumor cells. The mass is anterior to the anterior recess of the elbow, and lack of joint effusion is consistent with juxtaarticular but not intraarticular origin. (e) Photograph of the coronally sectioned gross specimen shows extensive calcification (*) superiorly.

View larger version (108K): [in this window] [in a new window] [Download PPT slide]   Figure 8e.  Extensively calcified synovial sarcoma in a 36-year-old woman who presented with a mass anterior to the elbow that had progressively enlarged over 15 months, resulting in a flexion deformity. (a) Lateral elbow radiograph shows a large calcified soft-tissue mass (arrows) anterior to the elbow without evidence of an effusion. (b) Axial CT scan also reveals the extensively calcified soft-tissue mass (arrows). (c, d) Coronal oblique T1-weighted (650/36) (c) and sagittal gradient-echo (1000/13/30°) (d) MR images demonstrate the large heterogeneous soft-tissue mass (arrowheads) with low- to intermediate-signal-intensity areas (*) corresponding to the calcifications seen on radiographs and CT scans. The extent of low to intermediate signal intensity is not as prominent as might be expected from the radiographic or CT appearance, likely related to intermixture with viable tumor cells. The mass is anterior to the anterior recess of the elbow, and lack of joint effusion is consistent with juxtaarticular but not intraarticular origin. (e) Photograph of the coronally sectioned gross specimen shows extensive calcification (*) superiorly.

View larger version (99K): [in this window] [in a new window] [Download PPT slide]   Figure 9a.  Synovial sarcoma of the thigh with extensive calcification and metastatic disease to the chest in a 52-year-old woman who presented with an enlarging soft-tissue mass in her thigh. (a) Axial postcontrast CT scan shows a large heterogeneous soft-tissue mass with both solid (arrows) and necrotic (N) regions and extensive calcification (arrowheads). (b) Coronal T2-weighted (2050/90) MR image reveals marked heterogeneity with the triple sign, including areas of high (H), intermediate (I), and low (L) signal intensity in the large soft-tissue mass. (c) Frontal chest radiograph demonstrates multiple pulmonary nodules (arrows) and a mediastinal mass (M). (d) Photograph of the sectioned gross specimen shows the large heterogeneous soft-tissue mass with hemorrhage (H) and large areas of calcification (C) that histologically (not shown) revealed metaplastic bone.

View larger version (121K): [in this window] [in a new window] [Download PPT slide]   Figure 9b.  Synovial sarcoma of the thigh with extensive calcification and metastatic disease to the chest in a 52-year-old woman who presented with an enlarging soft-tissue mass in her thigh. (a) Axial postcontrast CT scan shows a large heterogeneous soft-tissue mass with both solid (arrows) and necrotic (N) regions and extensive calcification (arrowheads). (b) Coronal T2-weighted (2050/90) MR image reveals marked heterogeneity with the triple sign, including areas of high (H), intermediate (I), and low (L) signal intensity in the large soft-tissue mass. (c) Frontal chest radiograph demonstrates multiple pulmonary nodules (arrows) and a mediastinal mass (M). (d) Photograph of the sectioned gross specimen shows the large heterogeneous soft-tissue mass with hemorrhage (H) and large areas of calcification (C) that histologically (not shown) revealed metaplastic bone.

View larger version (141K): [in this window] [in a new window] [Download PPT slide]   Figure 9c.  Synovial sarcoma of the thigh with extensive calcification and metastatic disease to the chest in a 52-year-old woman who presented with an enlarging soft-tissue mass in her thigh. (a) Axial postcontrast CT scan shows a large heterogeneous soft-tissue mass with both solid (arrows) and necrotic (N) regions and extensive calcification (arrowheads). (b) Coronal T2-weighted (2050/90) MR image reveals marked heterogeneity with the triple sign, including areas of high (H), intermediate (I), and low (L) signal intensity in the large soft-tissue mass. (c) Frontal chest radiograph demonstrates multiple pulmonary nodules (arrows) and a mediastinal mass (M). (d) Photograph of the sectioned gross specimen shows the large heterogeneous soft-tissue mass with hemorrhage (H) and large areas of calcification (C) that histologically (not shown) revealed metaplastic bone.

View larger version (106K): [in this window] [in a new window] [Download PPT slide]   Figure 9d.  Synovial sarcoma of the thigh with extensive calcification and metastatic disease to the chest in a 52-year-old woman who presented with an enlarging soft-tissue mass in her thigh. (a) Axial postcontrast CT scan shows a large heterogeneous soft-tissue mass with both solid (arrows) and necrotic (N) regions and extensive calcification (arrowheads). (b) Coronal T2-weighted (2050/90) MR image reveals marked heterogeneity with the triple sign, including areas of high (H), intermediate (I), and low (L) signal intensity in the large soft-tissue mass. (c) Frontal chest radiograph demonstrates multiple pulmonary nodules (arrows) and a mediastinal mass (M). (d) Photograph of the sectioned gross specimen shows the large heterogeneous soft-tissue mass with hemorrhage (H) and large areas of calcification (C) that histologically (not shown) revealed metaplastic bone.

View larger version (89K): [in this window] [in a new window] [Download PPT slide]   Figure 10a.  Synovial sarcoma of the foot with indolent erosion of bone in a 14-year-old girl with an enlarging foot mass. (a) Anteroposterior radiograph of the foot shows indolent extrinsic erosion of the second and third metatarsals (arrowheads). (b) CT scan reveals a small focus of nonspecific calcification (arrow) (not seen on the radiograph) in the soft-tissue mass, which extends between the first to third metatarsals (arrowheads). (c) Short axis T2-weighted (2100/90) MR image shows an intermediate-signal-intensity soft-tissue mass (*) with extension dorsally (white arrow) between the second and third metatarsals that causes the extrinsic erosion of bone (black arrow).

View larger version (71K): [in this window] [in a new window] [Download PPT slide]   Figure 10b.  Synovial sarcoma of the foot with indolent erosion of bone in a 14-year-old girl with an enlarging foot mass. (a) Anteroposterior radiograph of the foot shows indolent extrinsic erosion of the second and third metatarsals (arrowheads). (b) CT scan reveals a small focus of nonspecific calcification (arrow) (not seen on the radiograph) in the soft-tissue mass, which extends between the first to third metatarsals (arrowheads). (c) Short axis T2-weighted (2100/90) MR image shows an intermediate-signal-intensity soft-tissue mass (*) with extension dorsally (white arrow) between the second and third metatarsals that causes the extrinsic erosion of bone (black arrow).

View larger version (110K): [in this window] [in a new window] [Download PPT slide]   Figure 10c.  Synovial sarcoma of the foot with indolent erosion of bone in a 14-year-old girl with an enlarging foot mass. (a) Anteroposterior radiograph of the foot shows indolent extrinsic erosion of the second and third metatarsals (arrowheads). (b) CT scan reveals a small focus of nonspecific calcification (arrow) (not seen on the radiograph) in the soft-tissue mass, which extends between the first to third metatarsals (arrowheads). (c) Short axis T2-weighted (2100/90) MR image shows an intermediate-signal-intensity soft-tissue mass (*) with extension dorsally (white arrow) between the second and third metatarsals that causes the extrinsic erosion of bone (black arrow).

View larger version (154K): [in this window] [in a new window] [Download PPT slide]   Figure 11a.  Synovial sarcoma in the foot with bone invasion in a 29-year-old woman with a 10-year history of foot pain and treatment for plantar fasciitis without relief. (a, b) Short axis (a) and sagittal (b) T1-weighted MR images (750/19) show a multilobulated soft-tissue mass (*) with septa (arrowheads) in the plantar aspect of the midfoot. There is deep erosion and invasion of the third and fourth metatarsal bases (arrows). (c) Photograph of the sagittally sectioned gross specimen demonstrates identical features corresponding to the imaging findings: multilobulated soft-tissue mass (M) with deep erosion and invasion of the fourth metatarsal base (*). (d) Photograph of a sagittally sectioned whole-mounted specimen (H-E stain) from a different patient also reveals a synovial sarcoma in the plantar soft tissues (S) invading the metatarsal marrow (M).

View larger version (144K): [in this window] [in a new window] [Download PPT slide]   Figure 11b.  Synovial sarcoma in the foot with bone invasion in a 29-year-old woman with a 10-year history of foot pain and treatment for plantar fasciitis without relief. (a, b) Short axis (a) and sagittal (b) T1-weighted MR images (750/19) show a multilobulated soft-tissue mass (*) with septa (arrowheads) in the plantar aspect of the midfoot. There is deep erosion and invasion of the third and fourth metatarsal bases (arrows). (c) Photograph of the sagittally sectioned gross specimen demonstrates identical features corresponding to the imaging findings: multilobulated soft-tissue mass (M) with deep erosion and invasion of the fourth metatarsal base (*). (d) Photograph of a sagittally sectioned whole-mounted specimen (H-E stain) from a different patient also reveals a synovial sarcoma in the plantar soft tissues (S) invading the metatarsal marrow (M).

View larger version (77K): [in this window] [in a new window] [Download PPT slide]   Figure 11c.  Synovial sarcoma in the foot with bone invasion in a 29-year-old woman with a 10-year history of foot pain and treatment for plantar fasciitis without relief. (a, b) Short axis (a) and sagittal (b) T1-weighted MR images (750/19) show a multilobulated soft-tissue mass (*) with septa (arrowheads) in the plantar aspect of the midfoot. There is deep erosion and invasion of the third and fourth metatarsal bases (arrows). (c) Photograph of the sagittally sectioned gross specimen demonstrates identical features corresponding to the imaging findings: multilobulated soft-tissue mass (M) with deep erosion and invasion of the fourth metatarsal base (*). (d) Photograph of a sagittally sectioned whole-mounted specimen (H-E stain) from a different patient also reveals a synovial sarcoma in the plantar soft tissues (S) invading the metatarsal marrow (M).

View larger version (65K): [in this window] [in a new window] [Download PPT slide]   Figure 11d.  Synovial sarcoma in the foot with bone invasion in a 29-year-old woman with a 10-year history of foot pain and treatment for plantar fasciitis without relief. (a, b) Short axis (a) and sagittal (b) T1-weighted MR images (750/19) show a multilobulated soft-tissue mass (*) with septa (arrowheads) in the plantar aspect of the midfoot. There is deep erosion and invasion of the third and fourth metatarsal bases (arrows). (c) Photograph of the sagittally sectioned gross specimen demonstrates identical features corresponding to the imaging findings: multilobulated soft-tissue mass (M) with deep erosion and invasion of the fourth metatarsal base (*). (d) Photograph of a sagittally sectioned whole-mounted specimen (H-E stain) from a different patient also reveals a synovial sarcoma in the plantar soft tissues (S) invading the metatarsal marrow (M).

View larger version (114K): [in this window] [in a new window] [Download PPT slide]   Figure 12a.  Synovial sarcoma adjacent to the ankle in a 37-year-old woman with a soft-tissue mass noted after trauma and development of hematoma. (a) Angiogram shows dense tumor staining and neovascularity (arrowheads) of the large soft-tissue mass adjacent to the ankle. The posterior tibial artery is displaced (arrows). (b) Axial T2-weighted (2000/80) MR image reveals marked heterogeneity and multilobulation (bowl of grapes sign) with the triple sign (areas of high [H], intermediate [I], and low [L] signal intensity), fluid levels (arrowheads) resulting from hemorrhage, and cortical erosion (arrows). (c) Photograph of the sectioned gross specimen shows the multilobulated hemorrhagic morphology (*) corresponding to the MR imaging appearance.

View larger version (120K): [in this window] [in a new window] [Download PPT slide]   Figure 12b.  Synovial sarcoma adjacent to the ankle in a 37-year-old woman with a soft-tissue mass noted after trauma and development of hematoma. (a) Angiogram shows dense tumor staining and neovascularity (arrowheads) of the large soft-tissue mass adjacent to the ankle. The posterior tibial artery is displaced (arrows). (b) Axial T2-weighted (2000/80) MR image reveals marked heterogeneity and multilobulation (bowl of grapes sign) with the triple sign (areas of high [H], intermediate [I], and low [L] signal intensity), fluid levels (arrowheads) resulting from hemorrhage, and cortical erosion (arrows). (c) Photograph of the sectioned gross specimen shows the multilobulated hemorrhagic morphology (*) corresponding to the MR imaging appearance.

View larger version (129K): [in this window] [in a new window] [Download PPT slide]   Figure 12c.  Synovial sarcoma adjacent to the ankle in a 37-year-old woman with a soft-tissue mass noted after trauma and development of hematoma. (a) Angiogram shows dense tumor staining and neovascularity (arrowheads) of the large soft-tissue mass adjacent to the ankle. The posterior tibial artery is displaced (arrows). (b) Axial T2-weighted (2000/80) MR image reveals marked heterogeneity and multilobulation (bowl of grapes sign) with the triple sign (areas of high [H], intermediate [I], and low [L] signal intensity), fluid levels (arrowheads) resulting from hemorrhage, and cortical erosion (arrows). (c) Photograph of the sectioned gross specimen shows the multilobulated hemorrhagic morphology (*) corresponding to the MR imaging appearance.

View larger version (51K): [in this window] [in a new window] [Download PPT slide]   Figure 13a.  Synovial sarcoma of the foot in a 15-year-old girl with a 7-year history of a soft-tissue mass. The patient initially presented at age 8 years with a foot mass that was presumed to be a fibroma and was monitored; however, the patient developed increasing pain. (a) Lateral radiograph shows subtle fullness of the soft tissue in the plantar aspect of the foot (*). (b–d) Sagittal T1-weighted 550/20) images obtained without (b) and with (c) intravenous contrast material and T2-weighted (d, 2000/80) MR image show a heterogeneous plantar soft-tissue mass (large arrows). Fusiform shape is caused by location between osseous structures, including the calcaneus and bones of the midfoot. Prominent serpentine flow voids are seen with all pulse sequences (large arrowheads). There is diffuse heterogeneous enhancement following contrast material administration; however, the vascular channels remain low signal intensity due to high flow. Foci of increased signal intensity on the T1-weighted image (small arrowheads in b) and low signal intensity in the corresponding T2-weighted image (d) represent hemorrhage. (e) Blood flow images from bone scintigraphy reveal marked increased radionuclide uptake (arrows) reflecting the high degree of vascularity. (f) Photograph of the sagittally sectioned gross specimen demonstrates the fusiform-shaped synovial sarcoma (*) with several visible vessels (arrows).

View larger version (130K): [in this window] [in a new window] [Download PPT slide]   Figure 13b.  Synovial sarcoma of the foot in a 15-year-old girl with a 7-year history of a soft-tissue mass. The patient initially presented at age 8 years with a foot mass that was presumed to be a fibroma and was monitored; however, the patient developed increasing pain. (a) Lateral radiograph shows subtle fullness of the soft tissue in the plantar aspect of the foot (*). (b–d) Sagittal T1-weighted 550/20) images obtained without (b) and with (c) intravenous contrast material and T2-weighted (d, 2000/80) MR image show a heterogeneous plantar soft-tissue mass (large arrows). Fusiform shape is caused by location between osseous structures, including the calcaneus and bones of the midfoot. Prominent serpentine flow voids are seen with all pulse sequences (large arrowheads). There is diffuse heterogeneous enhancement following contrast material administration; however, the vascular channels remain low signal intensity due to high flow. Foci of increased signal intensity on the T1-weighted image (small arrowheads in b) and low signal intensity in the corresponding T2-weighted image (d) represent hemorrhage. (e) Blood flow images from bone scintigraphy reveal marked increased radionuclide uptake (arrows) reflecting the high degree of vascularity. (f) Photograph of the sagittally sectioned gross specimen demonstrates the fusiform-shaped synovial sarcoma (*) with several visible vessels (arrows).

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 13c.  Synovial sarcoma of the foot in a 15-year-old girl with a 7-year history of a soft-tissue mass. The patient initially presented at age 8 years with a foot mass that was presumed to be a fibroma and was monitored; however, the patient developed increasing pain. (a) Lateral radiograph shows subtle fullness of the soft tissue in the plantar aspect of the foot (*). (b–d) Sagittal T1-weighted 550/20) images obtained without (b) and with (c) intravenous contrast material and T2-weighted (d, 2000/80) MR image show a heterogeneous plantar soft-tissue mass (large arrows). Fusiform shape is caused by location between osseous structures, including the calcaneus and bones of the midfoot. Prominent serpentine flow voids are seen with all pulse sequences (large arrowheads). There is diffuse heterogeneous enhancement following contrast material administration; however, the vascular channels remain low signal intensity due to high flow. Foci of increased signal intensity on the T1-weighted image (small arrowheads in b) and low signal intensity in the corresponding T2-weighted image (d) represent hemorrhage. (e) Blood flow images from bone scintigraphy reveal marked increased radionuclide uptake (arrows) reflecting the high degree of vascularity. (f) Photograph of the sagittally sectioned gross specimen demonstrates the fusiform-shaped synovial sarcoma (*) with several visible vessels (arrows).

View larger version (125K): [in this window] [in a new window] [Download PPT slide]   Figure 13d.  Synovial sarcoma of the foot in a 15-year-old girl with a 7-year history of a soft-tissue mass. The patient initially presented at age 8 years with a foot mass that was presumed to be a fibroma and was monitored; however, the patient developed increasing pain. (a) Lateral radiograph shows subtle fullness of the soft tissue in the plantar aspect of the foot (*). (b–d) Sagittal T1-weighted 550/20) images obtained without (b) and with (c) intravenous contrast material and T2-weighted (d, 2000/80) MR image show a heterogeneous plantar soft-tissue mass (large arrows). Fusiform shape is caused by location between osseous structures, including the calcaneus and bones of the midfoot. Prominent serpentine flow voids are seen with all pulse sequences (large arrowheads). There is diffuse heterogeneous enhancement following contrast material administration; however, the vascular channels remain low signal intensity due to high flow. Foci of increased signal intensity on the T1-weighted image (small arrowheads in b) and low signal intensity in the corresponding T2-weighted image (d) represent hemorrhage. (e) Blood flow images from bone scintigraphy reveal marked increased radionuclide uptake (arrows) reflecting the high degree of vascularity. (f) Photograph of the sagittally sectioned gross specimen demonstrates the fusiform-shaped synovial sarcoma (*) with several visible vessels (arrows).

View larger version (83K): [in this window] [in a new window] [Download PPT slide]   Figure 13e.  Synovial sarcoma of the foot in a 15-year-old girl with a 7-year history of a soft-tissue mass. The patient initially presented at age 8 years with a foot mass that was presumed to be a fibroma and was monitored; however, the patient developed increasing pain. (a) Lateral radiograph shows subtle fullness of the soft tissue in the plantar aspect of the foot (*). (b–d) Sagittal T1-weighted 550/20) images obtained without (b) and with (c) intravenous contrast material and T2-weighted (d, 2000/80) MR image show a heterogeneous plantar soft-tissue mass (large arrows). Fusiform shape is caused by location between osseous structures, including the calcaneus and bones of the midfoot. Prominent serpentine flow voids are seen with all pulse sequences (large arrowheads). There is diffuse heterogeneous enhancement following contrast material administration; however, the vascular channels remain low signal intensity due to high flow. Foci of increased signal intensity on the T1-weighted image (small arrowheads in b) and low signal intensity in the corresponding T2-weighted image (d) represent hemorrhage. (e) Blood flow images from bone scintigraphy reveal marked increased radionuclide uptake (arrows) reflecting the high degree of vascularity. (f) Photograph of the sagittally sectioned gross specimen demonstrates the fusiform-shaped synovial sarcoma (*) with several visible vessels (arrows).

View larger version (105K): [in this window] [in a new window] [Download PPT slide]   Figure 13f.  Synovial sarcoma of the foot in a 15-year-old girl with a 7-year history of a soft-tissue mass. The patient initially presented at age 8 years with a foot mass that was presumed to be a fibroma and was monitored; however, the patient developed increasing pain. (a) Lateral radiograph shows subtle fullness of the soft tissue in the plantar aspect of the foot (*). (b–d) Sagittal T1-weighted 550/20) images obtained without (b) and with (c) intravenous contrast material and T2-weighted (d, 2000/80) MR image show a heterogeneous plantar soft-tissue mass (large arrows). Fusiform shape is caused by location between osseous structures, including the calcaneus and bones of the midfoot. Prominent serpentine flow voids are seen with all pulse sequences (large arrowheads). There is diffuse heterogeneous enhancement following contrast material administration; however, the vascular channels remain low signal intensity due to high flow. Foci of increased signal intensity on the T1-weighted image (small arrowheads in b) and low signal intensity in the corresponding T2-weighted image (d) represent hemorrhage. (e) Blood flow images from bone scintigraphy reveal marked increased radionuclide uptake (arrows) reflecting the high degree of vascularity. (f) Photograph of the sagittally sectioned gross specimen demonstrates the fusiform-shaped synovial sarcoma (*) with several visible vessels (arrows).

View larger version (145K): [in this window] [in a new window] [Download PPT slide]   Figure 14a.  Synovial sarcoma of the thigh with neurovascular encasement in a 29-year-old man who presented with persistent painless swelling. (a) Transverse sonogram reveals a heterogeneous mixed echogenicity soft-tissue mass (arrows). (b, c) Blood pool (b) and delayed static (c) images from bone scintigraphy demonstrate heterogeneous radionuclide uptake with central photopenia. (d, e) Axial T1-weighted (a, 600/30) and T2-weighted (b, 2000/100) MR images show a soft-tissue mass in the medial aspect of the right thigh (arrows). The soft-tissue mass encases the neurovascular bundle, including the superficial femoral vessels (arrowhead). A peripheral area of hemorrhage has high signal intensity (star) with both pulse sequences. (f, g) Photographs of the sectioned gross specimen following amputation shows the encasement of the neurovascular structures (arrowheads) by the tumor (*).

View larger version (83K): [in this window] [in a new window] [Download PPT slide]   Figure 14b.  Synovial sarcoma of the thigh with neurovascular encasement in a 29-year-old man who presented with persistent painless swelling. (a) Transverse sonogram reveals a heterogeneous mixed echogenicity soft-tissue mass (arrows). (b, c) Blood pool (b) and delayed static (c) images from bone scintigraphy demonstrate heterogeneous radionuclide uptake with central photopenia. (d, e) Axial T1-weighted (a, 600/30) and T2-weighted (b, 2000/100) MR images show a soft-tissue mass in the medial aspect of the right thigh (arrows). The soft-tissue mass encases the neurovascular bundle, including the superficial femoral vessels (arrowhead). A peripheral area of hemorrhage has high signal intensity (star) with both pulse sequences. (f, g) Photographs of the sectioned gross specimen following amputation shows the encasement of the neurovascular structures (arrowheads) by the tumor (*).

View larger version (76K): [in this window] [in a new window] [Download PPT slide]   Figure 14c.  Synovial sarcoma of the thigh with neurovascular encasement in a 29-year-old man who presented with persistent painless swelling. (a) Transverse sonogram reveals a heterogeneous mixed echogenicity soft-tissue mass (arrows). (b, c) Blood pool (b) and delayed static (c) images from bone scintigraphy demonstrate heterogeneous radionuclide uptake with central photopenia. (d, e) Axial T1-weighted (a, 600/30) and T2-weighted (b, 2000/100) MR images show a soft-tissue mass in the medial aspect of the right thigh (arrows). The soft-tissue mass encases the neurovascular bundle, including the superficial femoral vessels (arrowhead). A peripheral area of hemorrhage has high signal intensity (star) with both pulse sequences. (f, g) Photographs of the sectioned gross specimen following amputation shows the encasement of the neurovascular structures (arrowheads) by the tumor (*).

View larger version (165K): [in this window] [in a new window] [Download PPT slide]   Figure 14d.  Synovial sarcoma of the thigh with neurovascular encasement in a 29-year-old man who presented with persistent painless swelling. (a) Transverse sonogram reveals a heterogeneous mixed echogenicity soft-tissue mass (arrows). (b, c) Blood pool (b) and delayed static (c) images from bone scintigraphy demonstrate heterogeneous radionuclide uptake with central photopenia. (d, e) Axial T1-weighted (a, 600/30) and T2-weighted (b, 2000/100) MR images show a soft-tissue mass in the medial aspect of the right thigh (arrows). The soft-tissue mass encases the neurovascular bundle, including the superficial femoral vessels (arrowhead). A peripheral area of hemorrhage has high signal intensity (star) with both pulse sequences. (f, g) Photographs of the sectioned gross specimen following amputation shows the encasement of the neurovascular structures (arrowheads) by the tumor (*).

View larger version (157K): [in this window] [in a new window] [Download PPT slide]   Figure 14e.  Synovial sarcoma of the thigh with neurovascular encasement in a 29-year-old man who presented with persistent painless swelling. (a) Transverse sonogram reveals a heterogeneous mixed echogenicity soft-tissue mass (arrows). (b, c) Blood pool (b) and delayed static (c) images from bone scintigraphy demonstrate heterogeneous radionuclide uptake with central photopenia. (d, e) Axial T1-weighted (a, 600/30) and T2-weighted (b, 2000/100) MR images show a soft-tissue mass in the medial aspect of the right thigh (arrows). The soft-tissue mass encases the neurovascular bundle, including the superficial femoral vessels (arrowhead). A peripheral area of hemorrhage has high signal intensity (star) with both pulse sequences. (f, g) Photographs of the sectioned gross specimen following amputation shows the encasement of the neurovascular structures (arrowheads) by the tumor (*).

View larger version (111K): [in this window] [in a new window] [Download PPT slide]   Figure 14f.  Synovial sarcoma of the thigh with neurovascular encasement in a 29-year-old man who presented with persistent painless swelling. (a) Transverse sonogram reveals a heterogeneous mixed echogenicity soft-tissue mass (arrows). (b, c) Blood pool (b) and delayed static (c) images from bone scintigraphy demonstrate heterogeneous radionuclide uptake with central photopenia. (d, e) Axial T1-weighted (a, 600/30) and T2-weighted (b, 2000/100) MR images show a soft-tissue mass in the medial aspect of the right thigh (arrows). The soft-tissue mass encases the neurovascular bundle, including the superficial femoral vessels (arrowhead). A peripheral area of hemorrhage has high signal intensity (star) with both pulse sequences. (f, g) Photographs of the sectioned gross specimen following amputation shows the encasement of the neurovascular structures (arrowheads) by the tumor (*).

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 14g.  Synovial sarcoma of the thigh with neurovascular encasement in a 29-year-old man who presented with persistent painless swelling. (a) Transverse sonogram reveals a heterogeneous mixed echogenicity soft-tissue mass (arrows). (b, c) Blood pool (b) and delayed static (c) images from bone scintigraphy demonstrate heterogeneous radionuclide uptake with central photopenia. (d, e) Axial T1-weighted (a, 600/30) and T2-weighted (b, 2000/100) MR images show a soft-tissue mass in the medial aspect of the right thigh (arrows). The soft-tissue mass encases the neurovascular bundle, including the superficial femoral vessels (arrowhead). A peripheral area of hemorrhage has high signal intensity (star) with both pulse sequences. (f, g) Photographs of the sectioned gross specimen following amputation shows the encasement of the neurovascular structures (arrowheads) by the tumor (*).

The most common CT appearance of synovial sarcoma is that of a heterogeneous deep-seated soft-tissue mass with attenuation similar to or slightly lower than that of muscle (1,19,51–55) (Fig 8). Areas of lower attenuation representing necrosis or hemorrhage are also common (Figs 3, 8), although smaller lesions may be more homogeneous. In a minority of cases, low-attenuation areas may be the predominant CT feature, an appearance that simulates a hematoma or cystic mass (56). This CT appearance was described by Nakanisha et al (56) in seven patients and in 6% of 35 cases by Marzano and colleagues (51). Synovial sarcoma frequently demonstrates a multi-nodular morphology on CT scans. In a study by Tateishi and colleagues (52), a well-defined margin was observed in 53% of 30 lesions, compared with 47% that had an irregular margin. CT scans obtained after administration of intravenous contrast material show heterogeneous enhancement in 89%–100% of cases (52) (Fig 9). This feature is quite helpful for distinguishing those synovial sarcomas that initially appear as a cystic lesion or hematoma on precontrast images, as the heterogeneous enhancement pattern excludes these diagnoses (56). Nodular areas of enhancement may also be seen in these lesions (Fig 3).

CT is also useful for detecting calcification and bone involvement in synovial sarcoma, particularly in complex areas of the anatomy such as the pelvis, hip, or shoulder or when the lesions are small and subtle (57,58) (Fig 10). Calcification has been seen on CT images in 27%–41% of synovial sarcomas in the largest series by Tateishi et al (52) and Murphey et al (24). Calcification may also be identified in metastatic deposits, particularly in the lung, on CT scans. Bone involvement, either as erosion or marrow invasion, can be seen in nearly 25% of lesions in our experience (1,24, 43) (Fig 10).

With its superior contrast resolution, MR imaging is the optimal radiologic modality for assessing the extent and intrinsic characteristics of synovial sarcomas (similar to its ability to depict other soft-tissue tumors) for staging and diagnosis, respectively (25,59–64). On T1-weighted MR images, synovial sarcoma typically appears as a prominently heterogeneous multilobulated soft-tissue mass with signal intensity similar to or slightly higher than that of muscle (60–65). Prominent heterogeneity with predominant high signal intensity is also a feature of these lesions on T2-weighted MR images (60–65). This signal heterogeneity has been described as the triple sign by Jones and co-workers (25), represented by intermixed areas of low, intermediate, and high signal intensity on long repetition time images (Figs 9, 12, 15). This marked heterogeneity and triple sign on T2-weighted MR images is presumably the result of the mixture of solid cellular elements (intermediate signal intensity), hemorrhage or necrosis (high signal intensity), and calcified or fibrotic collagenized regions (low signal intensity). The triple sign has been described as occurring in 35%–57% of cases in larger series (25,51, 52). Based on our own experience, we agree that this feature is frequent in synovial sarcoma. However, the triple sign is also seen in other soft-tissue neoplasms, particularly malignant fibrous histiocytoma; therefore, this finding alone lacks a high degree of specificity. The multilobulated appearance with intervening septa described in 67%–75% of cases by Tateishi and colleagues (52) and by Blacksin and co-workers (65) (Figs 7, 11, 12, 16) is particularly well seen on T2-weighted images of larger lesions. Areas of hemorrhage, seen as fluid levels or foci of high signal intensity on T1- and T2-weighted MR images are frequent and are seen in up to 47% of cases (Figs 12, 16). Fluid levels have been described in 10%–25% of synovial sarcomas in several series. In our experience, this combination of features, particularly largely cystic areas or prominent hemorrhagic foci, often creates a bowl of grapes appearance (Fig 12). Smaller lesions (<5 cm at presentation) may have a predominantly homogeneous appearance on all MR images, regardless of pulse sequence, a finding that simulates a less aggressive process as described by Blacksin and coworkers (65) (Fig 17).

View larger version (135K): [in this window] [in a new window] [Download PPT slide]   Figure 15a.  Synovial sarcoma about the knee in a 46-year-old man with knee pain of several years duration and a progressively enlarging soft-tissue mass. (a–c) Coronal T1-weighted (600/18) MR images without (a) and with (b) intravenous contrast material and T2-weighted (c, 3000/108) MR image show a juxtaarticular heterogeneous soft-tissue mass (arrows) medial to the knee. The triple sign is present on the T2-weighted MR image (c), with the hemorrhagic nonenhancing high-signal-intensity regions (H, also high signal intensity on the T1-weighted image), a low-signal-intensity focus (arrowhead), and diffusely enhancing intermediate-signal-intensity cellular solid areas (*). (d) Photograph of the sectioned gross specimen also reveals solid (S) and hemorrhagic cystic (H) regions.

View larger version (156K): [in this window] [in a new window] [Download PPT slide]   Figure 15b.  Synovial sarcoma about the knee in a 46-year-old man with knee pain of several years duration and a progressively enlarging soft-tissue mass. (a–c) Coronal T1-weighted (600/18) MR images without (a) and with (b) intravenous contrast material and T2-weighted (c, 3000/108) MR image show a juxtaarticular heterogeneous soft-tissue mass (arrows) medial to the knee. The triple sign is present on the T2-weighted MR image (c), with the hemorrhagic nonenhancing high-signal-intensity regions (H, also high signal intensity on the T1-weighted image), a low-signal-intensity focus (arrowhead), and diffusely enhancing intermediate-signal-intensity cellular solid areas (*). (d) Photograph of the sectioned gross specimen also reveals solid (S) and hemorrhagic cystic (H) regions.

View larger version (118K): [in this window] [in a new window] [Download PPT slide]   Figure 15c.  Synovial sarcoma about the knee in a 46-year-old man with knee pain of several years duration and a progressively enlarging soft-tissue mass. (a–c) Coronal T1-weighted (600/18) MR images without (a) and with (b) intravenous contrast material and T2-weighted (c, 3000/108) MR image show a juxtaarticular heterogeneous soft-tissue mass (arrows) medial to the knee. The triple sign is present on the T2-weighted MR image (c), with the hemorrhagic nonenhancing high-signal-intensity regions (H, also high signal intensity on the T1-weighted image), a low-signal-intensity focus (arrowhead), and diffusely enhancing intermediate-signal-intensity cellular solid areas (*). (d) Photograph of the sectioned gross specimen also reveals solid (S) and hemorrhagic cystic (H) regions.

View larger version (109K): [in this window] [in a new window] [Download PPT slide]   Figure 15d.  Synovial sarcoma about the knee in a 46-year-old man with knee pain of several years duration and a progressively enlarging soft-tissue mass. (a–c) Coronal T1-weighted (600/18) MR images without (a) and with (b) intravenous contrast material and T2-weighted (c, 3000/108) MR image show a juxtaarticular heterogeneous soft-tissue mass (arrows) medial to the knee. The triple sign is present on the T2-weighted MR image (c), with the hemorrhagic nonenhancing high-signal-intensity regions (H, also high signal intensity on the T1-weighted image), a low-signal-intensity focus (arrowhead), and diffusely enhancing intermediate-signal-intensity cellular solid areas (*). (d) Photograph of the sectioned gross specimen also reveals solid (S) and hemorrhagic cystic (H) regions.

View larger version (137K): [in this window] [in a new window] [Download PPT slide]   Figure 16a.  Synovial sarcoma of the popliteal fossa with a large cystic component in a 39-year-old woman who presented with a slow-growing soft-tissue mass. (a–c) Axial T1-weighted (a, 500/12), sagittal T2-weighted (3575/90) fat-suppressed (b), and sagittal T1-weighted (637/9) fat-suppressed postcontrast (c) MR images show a large multilobulated popliteal soft-tissue mass (large arrows). Large nonenhancing hemorrhagic regions (H) with fluid levels (small arrows) are prominent (bowl of grapes sign) with intervening septa (arrowheads). Solid viable regions of the tumor (*) reveal diffuse enhancement and intermediate signal intensity on the long repetition time image (b). (d) Photograph of the sectioned gross specimen shows hemorrhagic cystic areas (H) and solid regions (S) that correlate with the imaging appearance.

View larger version (103K): [in this window] [in a new window] [Download PPT slide]   Figure 16b.  Synovial sarcoma of the popliteal fossa with a large cystic component in a 39-year-old woman who presented with a slow-growing soft-tissue mass. (a–c) Axial T1-weighted (a, 500/12), sagittal T2-weighted (3575/90) fat-suppressed (b), and sagittal T1-weighted (637/9) fat-suppressed postcontrast (c) MR images show a large multilobulated popliteal soft-tissue mass (large arrows). Large nonenhancing hemorrhagic regions (H) with fluid levels (small arrows) are prominent (bowl of grapes sign) with intervening septa (arrowheads). Solid viable regions of the tumor (*) reveal diffuse enhancement and intermediate signal intensity on the long repetition time image (b). (d) Photograph of the sectioned gross specimen shows hemorrhagic cystic areas (H) and solid regions (S) that correlate with the imaging appearance.

View larger version (125K): [in this window] [in a new window] [Download PPT slide]   Figure 16c.  Synovial sarcoma of the popliteal fossa with a large cystic component in a 39-year-old woman who presented with a slow-growing soft-tissue mass. (a–c) Axial T1-weighted (a, 500/12), sagittal T2-weighted (3575/90) fat-suppressed (b), and sagittal T1-weighted (637/9) fat-suppressed postcontrast (c) MR images show a large multilobulated popliteal soft-tissue mass (large arrows). Large nonenhancing hemorrhagic regions (H) with fluid levels (small arrows) are prominent (bowl of grapes sign) with intervening septa (arrowheads). Solid viable regions of the tumor (*) reveal diffuse enhancement and intermediate signal intensity on the long repetition time image (b). (d) Photograph of the sectioned gross specimen shows hemorrhagic cystic areas (H) and solid regions (S) that correlate with the imaging appearance.

View larger version (145K): [in this window] [in a new window] [Download PPT slide]   Figure 16d.  Synovial sarcoma of the popliteal fossa with a large cystic component in a 39-year-old woman who presented with a slow-growing soft-tissue mass. (a–c) Axial T1-weighted (a, 500/12), sagittal T2-weighted (3575/90) fat-suppressed (b), and sagittal T1-weighted (637/9) fat-suppressed postcontrast (c) MR images show a large multilobulated popliteal soft-tissue mass (large arrows). Large nonenhancing hemorrhagic regions (H) with fluid levels (small arrows) are prominent (bowl of grapes sign) with intervening septa (arrowheads). Solid viable regions of the tumor (*) reveal diffuse enhancement and intermediate signal intensity on the long repetition time image (b). (d) Photograph of the sectioned gross specimen shows hemorrhagic cystic areas (H) and solid regions (S) that correlate with the imaging appearance.

View larger version (137K): [in this window] [in a new window] [Download PPT slide]   Figure 17a.  Small synovial sarcoma adjacent to the elbow with well-defined margins in a 16-year-old boy with a 1-year history of pain and swelling. (a, b) Sagittal T1-weighted (a, 383/8) and axial fat-suppressed proton-density-weighted (b, 2700/32) MR images show a small well-defined homogeneous soft-tissue mass (arrows) adjacent to the anterior recess of the elbow joint. There is a mild lobulation at the lesion margins. (c) Photograph of the sectioned gross specimen reveals a small well-defined relatively homogeneous soft-tissue mass (M) with mildly lobulated margins that corresponds to the imaging findings.

View larger version (138K): [in this window] [in a new window] [Download PPT slide]   Figure 17b.  Small synovial sarcoma adjacent to the elbow with well-defined margins in a 16-year-old boy with a 1-year history of pain and swelling. (a, b) Sagittal T1-weighted (a, 383/8) and axial fat-suppressed proton-density-weighted (b, 2700/32) MR images show a small well-defined homogeneous soft-tissue mass (arrows) adjacent to the anterior recess of the elbow joint. There is a mild lobulation at the lesion margins. (c) Photograph of the sectioned gross specimen reveals a small well-defined relatively homogeneous soft-tissue mass (M) with mildly lobulated margins that corresponds to the imaging findings.

View larger version (111K): [in this window] [in a new window] [Download PPT slide]   Figure 17c.  Small synovial sarcoma adjacent to the elbow with well-defined margins in a 16-year-old boy with a 1-year history of pain and swelling. (a, b) Sagittal T1-weighted (a, 383/8) and axial fat-suppressed proton-density-weighted (b, 2700/32) MR images show a small well-defined homogeneous soft-tissue mass (arrows) adjacent to the anterior recess of the elbow joint. There is a mild lobulation at the lesion margins. (c) Photograph of the sectioned gross specimen reveals a small well-defined relatively homogeneous soft-tissue mass (M) with mildly lobulated margins that corresponds to the imaging findings.

MR imaging performed after intravenous injection of contrast material typically shows prominent enhancement in synovial sarcomas. The enhancement is more commonly heterogeneous (83%–100% of lesions) than homogeneous (0%–17% of lesions) (24,25,64). This heterogeneous enhancement reflects the intermixture of nonenhancing necrotic, cystic, or hemorrhagic regions and enhancing solid regions. The pattern of contrast enhancement may be diffuse when the majority of the tumor is viable, or, in largely necrotic lesions, it may appear peripheral or nodular with or without thick septa (>3 mm) (Fig 16). In approximately one-third of synovial sarcomas, we have noted serpentine vascular channels, a feature that is unusual in many other soft-tissue neoplasms (24) (Fig 13). The identification of these vascular channels largely limits the radiologic differential diagnosis to alveolar soft part sarcoma, metastatic renal carcinoma, hemangiopericytoma, hemangioendothelioma, rhabdomyosarcoma, extraskeletal Ewing sarcoma, and synovial sarcoma. The dynamic contrast-enhanced MR imaging appearance of synovial sarcoma has been described by van Rijswijk and colleagues (66) in 10 patients. In their study, 60% of cases showed rapid progressive linear increase in signal intensity followed by washout (five of six patients) or plateau (one patient), whereas 40% revealed a late sustained increase in enhancement after the initial rapid enhancement (66). The only pharmokinetic feature highly associated with malignancy that was seen in all 10 synovial sarcomas was early enhancement within 7 seconds following arterial enhancement (66). The pattern of initial enhancement was diffuse (40% of cases), heterogeneous (40%), or peripheral (20%) (66). Contrast material enhancement can be particularly important for distinguishing synovial sarcomas with predominantly cystic characteristics with standard T1- and T2-weighted sequences (57) (Fig 16). In these lesions, solid nodular foci of enhancement are invariably seen, findings that represent viable nonnecrotic regions (Fig 16). Recognition of these solid areas is particularly important, as imaging guidance (with either CT or US) may be required to direct biopsy of these foci that harbor diagnostic tissue for our pathology colleagues, leading to the correct diagnosis. We have never seen (nor has any case been reported in the literature, to the best of our knowledge) a synovial sarcoma that truly simulates a cyst on contrast-enhanced MR images (thin peripheral and septal enhancement only).

The prognostic significance of imaging features (CT and MR) for synovial sarcoma was recently described by Tateishi and co-workers (52). Statistically significant imaging features that favored a high-grade synovial sarcoma included absence of calcification, presence of cystic components, presence of hemorrhage, and presence of the triple sign (52). Imaging findings that were seen only with high-grade lesions were cystic components, hemorrhage, fluid levels, and the triple sign (52). In addition, Tateishi and colleagues (52) observed a statistically significant improvement in disease-free survival for patients whose lesions had calcification but no hemorrhage or triple sign. Metastases-free survival was statistically significantly increased for patients whose lesions had internal septa but no fluid levels (52). We are not aware of any studies that have shown any significant imaging differences between monophasic and biphasic synovial sarcomas.

Following chemotherapy or radiation therapy, increasing signal intensity may be seen within the synovial sarcoma on T2-weighted MR images, a finding that corresponds to progressive necrosis. Tumor size may also show a reduction in response to this therapy. Edema surrounding the tumor, typically not a significant feature before therapy, may also develop subsequent to adjuvant treatment. These posttreatment changes are often not apparent on short echo time images.

	Treatment and Prognosis

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

 
As with many intermediate- to high-grade primary malignant soft-tissue neoplasms, local control of synovial sarcoma is primarily achieved with surgery. In the past, the standard treatment of synovial sarcoma was radical surgical excision (removal of the entire tumor and anatomic compartment involved) with limb-sparing surgery if possible. However, because synovial sarcoma commonly occurs near large joints and neurovascular structures, radical surgical excision that leaves an adequately functional limb may be difficult or impossible. For that reason, the current treatment of choice is wide local excision (removal of the tumor, its pseudocapsule, and a normal cuff of surrounding tissue). The surgical margins should be closely evaluated to determine the need for adjuvant therapy. As expected, marginal excision (surgical dissection plane passing through the pseudocapsule) of the synovial sarcoma without removing an adequate rim of normal surrounding tissue is associated with high local recurrence rates (70%–83%) (67) (Fig 18). Amputation should be reserved for those cases in which gross resection of the tumor and preservation of a functional limb is not possible.

View larger version (65K): [in this window] [in a new window] [Download PPT slide]   Figure 18a.  Recurrent synovial sarcoma of the finger in a 19-year-old man who had undergone resection and radiation therapy 1 year before. (a, b) Axial T1-weighted (550/20) (a) and sagittal T2-weighted (3984/94) (b) fat-suppressed MR images show a multilobulated recurrent soft-tissue mass (*) with septa (arrowheads) surrounding the flexor tendon (T). There is intermediate signal intensity with both pulse sequences. (c, d) Photographs of the gross specimen both before (c) and after (d) longitudinal sectioning reveal the multilobular growth (*) with septa surrounding the flexor tendon (T), corresponding to the imaging findings.

View larger version (104K): [in this window] [in a new window] [Download PPT slide]   Figure 18b.  Recurrent synovial sarcoma of the finger in a 19-year-old man who had undergone resection and radiation therapy 1 year before. (a, b) Axial T1-weighted (550/20) (a) and sagittal T2-weighted (3984/94) (b) fat-suppressed MR images show a multilobulated recurrent soft-tissue mass (*) with septa (arrowheads) surrounding the flexor tendon (T). There is intermediate signal intensity with both pulse sequences. (c, d) Photographs of the gross specimen both before (c) and after (d) longitudinal sectioning reveal the multilobular growth (*) with septa surrounding the flexor tendon (T), corresponding to the imaging findings.

View larger version (61K): [in this window] [in a new window] [Download PPT slide]   Figure 18c.  Recurrent synovial sarcoma of the finger in a 19-year-old man who had undergone resection and radiation therapy 1 year before. (a, b) Axial T1-weighted (550/20) (a) and sagittal T2-weighted (3984/94) (b) fat-suppressed MR images show a multilobulated recurrent soft-tissue mass (*) with septa (arrowheads) surrounding the flexor tendon (T). There is intermediate signal intensity with both pulse sequences. (c, d) Photographs of the gross specimen both before (c) and after (d) longitudinal sectioning reveal the multilobular growth (*) with septa surrounding the flexor tendon (T), corresponding to the imaging findings.

View larger version (85K): [in this window] [in a new window] [Download PPT slide]   Figure 18d.  Recurrent synovial sarcoma of the finger in a 19-year-old man who had undergone resection and radiation therapy 1 year before. (a, b) Axial T1-weighted (550/20) (a) and sagittal T2-weighted (3984/94) (b) fat-suppressed MR images show a multilobulated recurrent soft-tissue mass (*) with septa (arrowheads) surrounding the flexor tendon (T). There is intermediate signal intensity with both pulse sequences. (c, d) Photographs of the gross specimen both before (c) and after (d) longitudinal sectioning reveal the multilobular growth (*) with septa surrounding the flexor tendon (T), corresponding to the imaging findings.

Radiation therapy plays an important role in the treatment of marginally resected tumors (74,75). Radiation therapy should be initiated preoperatively if the surgeon believes that the surgical margins will be positive or close. If the margins are microscopically positive in a mass that was thought to be easily resectable in a wide local fashion, radiation should be given postoperatively. In 1965, Cadman and co-workers (8) reported the results of treatment in 134 cases of synovial sarcoma. They showed a reduction in local recurrence from 92% to 50% for patients treated with local excision versus those treated with local excision followed by postoperative radiation therapy. However, 64% of those patients with synovial sarcoma of the extremity treated with either amputation or wide local excision and radiation therapy eventually died of metastatic disease (8). In 1994, Mullen and Zagars (76) demonstrated 5-, 10-, and 15-year survival rates of 76%, 63%, and 57%, respectively, for synovial sarcoma patients treated with conservative surgery and radiation therapy. More recently, Ferrari and colleagues (16) reported a 5-year local-recurrence-free survival rate following marginal resection with postoperative irradiation of 57% versus 7% for patients who did not undergo radiation therapy. There was no statistically significant difference in survival rates for patients whose synovial sarcomas were completely resected (16).

Patients with synovial sarcoma, since it is an intermediate- to high-grade sarcoma, have a 5-year survival rate ranging from 36% to 76%. At 10 years, the survival rate has been reported to range from 20% to 63% (16). The clinical course of synovial sarcoma is characterized by a high rate of local recurrence and metastatic disease. Local recurrence following resection occurs in 30%–50% of patients, and distant metastasis develops in 41% (16) (Fig 18). The majority of metastases occur within the first 2–5 years after treatment. However, there are numerous reports of late metastases occurring up to 26 years after the initial diagnosis, which likely reduces the 10-year versus 5-year survival rates. Metastases are present in 16%–25% of patients at their initial presentation (77,78). The most frequent metastatic site is the lung, which is affected in 94% of cases, followed by lymph nodes (4%–18%) and bone (8%–11%) (1–5,16,77,78) (Fig 9).

Multiple clinical and pathologic factors, including tumor size, location, patient age, and presence of poorly differentiated areas, have prognostic significance. Tumor size greater than 5 cm at presentation has the greatest impact on prognosis, with studies showing 5-year survival rates of 64% and 26% for patients with tumors less than 5 cm and those with masses greater than 5 cm, respectively (16,53). Patients with tumors in the extremities have a more favorable prognosis than those with lesions in the head and neck area or axially, a feature that likely reflects better surgical control available for extremity lesions. Deshmukh and colleagues (15) reported a poorer prognosis for patients with synovial sarcomas located in the proximal extremities. Others have reported better prognosis for patients with tumors located in the upper extremities compared with those with lower extremity lesions (31). Patient age of less than 15–20 years is also associated with a better long-term prognosis (79,80). Varela-Duran and Enzinger (81) reported that the presence of extensive calcifications suggests improved long-term survival, with 5-year survival rates of 82% and decreased rates of local recurrence (32%) and metastatic disease (29%). There is considerable controversy about the prognostic significance of tumor cell type (monophasic or biphasic). Although some authors report more indolent behavior with biphasic synovial sarcomas compared with monophasic synovial sarcomas (16), other authors have found no statistically significant outcome (79,82). However, the poorly differentiated subtype is associated with a worsened prognosis, with a 5-year survival rate of only 20%–30% (83,84). In addition, the presence of 20% or greater areas of poorly differentiated components is associated with an adverse outcome (31). Other pathologic factors associated with worsened prognosis include presence of rhabdoid cells, extensive tumor necrosis, high nuclear grade, p53 mutations, and high mitotic rate (>10 mitoses/10 high-power field) (2–5,85). More recently, the gene fusion type SYT-SSX2 (more common in monophasic lesions) has been associated with an improved prognosis, compared with that for SYT-SSX1, and an 89% metastasis-free survival (2–5,86,87).

	Summary

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

 
Synovial sarcoma is the fourth most common malignant primary soft-tissue neoplasm. The radiologic manifestations and spectrum of synovial sarcoma reflect the underlying pathologic appearance. We have reviewed, illustrated, and correlated the clinical, pathologic, and radiologic features of synovial sarcoma as well as the treatment and prognosis. Although the radiographic characteristics of synovial sarcoma are not pathognomonic, the findings of a soft-tissue mass, particularly if calcified, near but not in a joint in a young patient (15–40 years of age) are very suggestive of this diagnosis. Cross-sectional imaging features are vital for staging extent and for planning surgical resection. They also frequently reveal suggestive appearances of multilobulation and marked heterogeneity (creating the triple sign) with hemorrhage, fluid levels, and septa (creating the bowl of grapes sign). Two features associated with synovial sarcoma that may lead to an initial mistaken diagnosis of a benign indolent process are slow growth (average time to diagnosis, 2–4 years) and small size (<5 cm at initial presentation); in addition, these lesions may demonstrate well-defined margins and homogeneous appearance on cross-sectional images. Synovial sarcoma is an intermediate- to high-grade lesion, and, despite initial aggressive wide surgical resection, local recurrence and metastatic disease are common and prognosis is guarded. Understanding and recognizing the spectrum of radiologic appearances and their pathologic bases allow improved patient assessment and are important for optimal clinical management.

	Acknowledgments

 
The authors gratefully acknowledge the residents, without whom this project would not be possible, who attend the AFIP’s radiologic pathology courses (past, present, and future) for their contribution to our series of patients.

	Footnotes

 

Abbreviations: H-E = hematoxylineosin, STIR = short inversion time inversion recovery

The opinions or assertions contained herein are the private views of the authors and are not to be construed as official nor as reflecting the views of the Departments of the Army, Navy or Defense.

	References

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Clinical Characteristics Pathologic Features Imaging Features Treatment and Prognosis Summary References

 

1. Kransdorf MJ, Murphey MD. Imaging of soft tissue tumors. 2nd ed. Philadelphia, Pa: Lippincott William & Wilkins, 2006.
2. Weiss SW, Goldblum JR. Malignant soft tissue tumors of uncertain type. In: Weiss SW, Goldblum JR, eds. Enzinger and Weiss’s soft tissue tumors. 4th ed. St Louis, Mo: Mosby, 2001; 1483–1565.
3. Miettinen M. Soft tissue tumors with epithelial differentiation. In: Diagnostic soft tissue pathology. New York, NY: Churchill Livingstone, 2003; 463–468.
4. Fisher C, de Bruijn DRH, Geurts van Kessel A. Synovial sarcoma. In: Fletcher CD, Unni KK, Mertens F, eds. World Health Organization Classification of Tumors. Pathology and genetics of tumours of soft tissue and bone. Lyon, France: IARC, 2002.
5. Kempson RL, Fletcher CD, Evans HL, Hendrickson MR, Sibley RK. Tumors of uncertain and nonmesenchymal differentiation. In: Atlas of tumor pathology: tumors of the soft tissues. Washington, DC: Armed Forces Institute of Pathology, 2001; 472–484.
6. Pack GT, Ariel IM. Synovial sarcoma (malignant synovioma): a report of 60 cases. Surgery 1950;28: 1047–1084.[Medline]
7. Hare HF, Cerny MJ Jr. Soft tissue sarcoma: a review of 200 cases. Cancer 1963;16:1332–1337.[CrossRef][Medline]
8. Cadman NL, Soule EH, Kelly PJ. Synovial sarcoma: an analysis of 34 tumors. Cancer 1965;18: 613–627.[CrossRef][Medline]
9. Kransdorf MJ. Malignant soft-tissue tumors in a large referral population: distribution of diagnoses by age, sex, and location. AJR Am J Roentgenol 1995;164:129–134.[Abstract/Free Full Text]
10. Thompson DE, Frost HM, Hendrick JW, Horn RC Jr. Soft tissue sarcomas involving the extremities and the limb girdles: a review. South Med J 1971;64:33–44.[Medline]
11. Tsujimoto M, Aozasa K, Ueda T, et al. Soft tissue sarcomas in Osaka, Japan (1962–1985): review of 290 cases. Jpn J Clin Oncol 1988;18:231–234.[Abstract/Free Full Text]
12. Gustafson P. Soft tissue sarcoma: epidemiology and prognosis in 508 patients. Acta Orthop Scand Suppl 1994;259:1–31.[Medline]
13. Trassard M, Le Doussal V, Hacene K, et al. Prognostic factors in localized primary synovial sarcoma: a multicenter study of 128 adult patients. J Clin Oncol 2001;19:525–534.[Abstract/Free Full Text]
14. Spillane AJ, A’Hern R, Judson IR, Fisher C, Thomas JM. Synovial sarcoma: a clinicopathologic, staging, and prognostic assessment. J Clin Oncol 2000;18:3794–3803.[Abstract/Free Full Text]
15. Deshmukh R, Mankin HJ, Singer S. Synovial sarcoma: the importance of size and location for survival. Clin Orthop Relat Res 2004;419:155–161.
16. Ferrari A, Gronchi A, Casanova M, et al. Synovial sarcoma: a retrospective analysis of 271 patients of all ages treated at a single institution. Cancer 2004;101:627–634.[CrossRef][Medline]
17. Lewis JJ, Antonescu CR, Leung DH, et al. Synovial sarcoma: a multivariate analysis of prognostic factors in 112 patients with primary localized tumors of the extremity. J Clin Oncol 2000;18: 2087–2094.[Abstract/Free Full Text]
18. Skytting BT, Bauer HC, Perfekt R, et al. Clinical course in synovial sarcoma: a Scandinavian sarcoma group study of 104 patients. Acta Orthop Scand 1999;70:536–542.[Medline]
19. Israels SJ, Chan HS, Daneman A, Weitzman SS. Synovial sarcoma in childhood. AJR Am J Roentgenol 1984;142:803–806.[Abstract/Free Full Text]
20. Gurney JG, Young JL, Roffers SD, Smith MA, Bunin GR. Soft tissue sarcomas. In: Ries LA, Smith MA, Gurney JG, et al, eds. Cancer incidence and survival among children and adolescents: United States SEER Program 1975–1995. Bethesda, Md: National Cancer Institute, 1999; 112–123.
21. Nakajo M, Ohkubo K, Nandate T, et al. Primary synovial sarcoma of the sternum: computed tomography and magnetic resonance imaging findings. Radiat Med 2005;23:208–212.[Medline]
22. Song H, Koh BH, Cho OK, et al. Primary retro-peritoneal synovial sarcoma: a case report. J Korean Med Sci 2002;17:419–422.[Medline]
23. Matsuo Y, Sakai S, Yabuuchi H, et al. A case of pulmonary synovial sarcoma diagnosed with detection of chimera gene: imaging findings. Clin Imaging 2006;30:60–62.[CrossRef][Medline]
24. Murphey MD, Jelinek JS, Kransdorf MJ, Flemming DJ, Temple HT, Smith SE. Imaging of synovial sarcoma [abstract]. Radiology 1998;209(P): 421.
25. Jones BC, Sundaram M, Kransdorf MJ. Synovial sarcoma: MR imaging findings in 34 patients. AJR Am J Roentgenol 1993;161:827–830.[Abstract/Free Full Text]
26. Miettinen M, Virtanen I. Synovial sarcoma: a misnomer. Am J Pathol 1984;117:18–25.[Abstract]
27. Miettinen M. Keratin subsets in spindle cell sarcomas: keratins are widespread but synovial sarcoma contains a distinctive keratin polypeptide pattern and desmoplakins. Am J Pathol 1991;138:505–513.[Abstract]
28. Fisher C. Synovial sarcoma. Ann Diagn Pathol 1998;2:401–421.[CrossRef][Medline]
29. Katenkamp D, Hunerbein R. The prognostic significance of inflammatory cells in malignant human soft tissue tumors: malignancy grading [in German]. Zentralbl Pathol 1992;138:21–25.[Medline]
30. Milchgrub S, Ghandur-Mnaymneh L, Dorfman HD, Albores-Saavedra J. Synovial sarcoma with extensive osteoid and bone formation. Am J Surg Pathol 1993;17:357–363.[Medline]
31. Machen SK, Easley KA, Goldblum JR. Synovial sarcoma of the extremities: a clinicopathologic study of 34 cases, including semi-quantitative analysis of spindled, epithelial, and poorly differentiated areas. Am J Surg Pathol 1999;23:268–275.[CrossRef][Medline]
32. Chan JA, McMenamin ME, Fletcher CD. Synovial sarcoma in older patients: clinicopathological analysis of 32 cases with emphasis on unusual histological features. Histopathology 2003;43:72–83.[CrossRef][Medline]
33. van de Rijn M, Barr FG, Xiong QB, Hedges M, Shipley J, Fisher C. Poorly differentiated synovial sarcoma: an analysis of clinical, pathologic, and molecular genetic features. Am J Surg Pathol 1999;23:106–112.[CrossRef][Medline]
34. Coindre JM, Trojani M, Contesso G, et al. Reproducibility of a histopathologic grading system for adult soft tissue sarcoma. Cancer 1986;58:306–309.[CrossRef][Medline]
35. Coindre JM, Terrier P, Guillou L, et al. Predictive value of grade for metastasis development in the main histologic types of adult soft tissue sarcomas: a study of 1240 patients from the French Federation of Cancer Centers Sarcoma Group. Cancer 2001;91:1914–1926.[CrossRef][Medline]
36. Folpe AL, Schmidt RA, Chapman D, Gown AM. Poorly differentiated synovial sarcoma: immunohistochemical distinction from primitive neuroectodermal tumors and high-grade malignant peripheral nerve sheath tumors. Am J Surg Pathol 1998;22:673–682.[CrossRef][Medline]
37. Corson JM, Weiss LM, Banks-Schlegel SP, Pinkus GS. Keratin proteins in synovial sarcoma. Am J Surg Pathol 1983;7:107–109.[Medline]
38. Miettinen M, Limon J, Niezabitowski A, Lasota J. Patterns of keratin polypeptides in 110 biphasic, monophasic, and poorly differentiated synovial sarcomas. Virchows Arch 2000;437:275–283.[CrossRef][Medline]
39. Machen SK, Fisher C, Gautam RS, Tubbs RR, Goldblum JR. Utility of cytokeratin subsets for distinguishing poorly differentiated synovial sarcoma from peripheral primitive neuroectodermal tumour. Histopathology 1998;33:501–507.[CrossRef][Medline]
40. Laskin WB, Miettinen M. Epithelial-type and neural-type cadherin expression in malignant non-carcinomatous neoplasms with epithelioid features that involve the soft tissues. Arch Pathol Lab Med 2002;126:425–431.[Medline]
41. Guillou L, Benhattar J, Bonichon F, et al. Histologic grade, but not SYT-SSX fusion type, is an important prognostic factor in patients with synovial sarcoma: a multicenter, retrospective analysis. J Clin Oncol 2004;22:4040–4050.[Abstract/Free Full Text]
42. van de Rijn M, Barr FG, Collins MH, Xiong QB, Fisher C. Absence of SYT-SSX fusion products in soft tissue tumors other than synovial sarcoma. Am J Clin Pathol 1999;112:43–49.[Medline]
43. Horowitz AL, Resnick D, Watson RC. The roentgen features of synovial sarcomas. Clin Radiol 1973;24:481–484.[CrossRef][Medline]
44. Sanchez Reyes JM, Alcaraz Mexia M, Quinones Tapia D, Aramburu JA. Extensively calcified synovial sarcoma. Skeletal Radiol 1997;26:671–673.[CrossRef][Medline]
45. Maxwell JR, Yao L, Eckardt JJ, Doberneck SA. Case report 878: densely calcifying synovial sarcoma of the hip metastatic to the lungs. Skeletal Radiol 1994;23:673–675.[Medline]
46. Strickland B, Mackenzie M. Bone involvement in synovial sarcoma. J Fac Radiol 1959;10:64.[CrossRef]
47. Blacksin M, Adesokan A, Benevenia J. Case report 871: synovial sarcoma, monophasic type. Skeletal Radiol 1994;23:589–591.[Medline]
48. Braeuning MP, Park HM. Three-phase Tc-99m MDP scan findings of a soft tissue sarcoma. Clin Nucl Med 1990;15:572–573.[CrossRef][Medline]
49. Rice S, Stewart CA. Synovial sarcoma seen on bone scan. Clin Nucl Med 1990;15:445–446.[CrossRef][Medline]
50. Nair N, Basu S. Unsuspected metastatic male breast nodule from synovial sarcoma detected by FDG PET. Clin Nucl Med 2005;30:289–290.[CrossRef][Medline]
51. Marzano L, Failoni S, Gallazzi M, Garbagna P. The role of diagnostic imaging in synovial sarcoma: our experience. Radiol Med (Torino) 2004; 107:533–540.
52. Tateishi U, Hasegawa T, Beppu Y, Satake M, Moriyama N. Synovial sarcoma of the soft tissues: prognostic significance of imaging features. J Comput Assist Tomogr 2004;28:140–148.[CrossRef][Medline]
53. Rangheard AS, Vanel D, Viala J, Schwaab G, Casiraghi O, Sigal R. Synovial sarcomas of the head and neck: CT and MR imaging findings of eight patients. AJNR Am J Neuroradiol 2001;22:851–857.[Abstract/Free Full Text]
54. Ko SF, Chou FF, Huang CH, et al. Primary synovial sarcoma of the gastrocolic ligament. Br J Radiol 1998;71:438–440.[Abstract]
55. Meyer CA, Kransdorf MJ, Moser RP Jr, Jelinek JS. Case report 716: soft-tissue metastasis in synovial sarcoma. Skeletal Radiol 1992;21:128–131.[Medline]
56. Nakanishi H, Araki N, Sawai Y, et al. Cystic synovial sarcomas: imaging features with clinical and histopathologic correlation. Skeletal Radiol 2003; 32:701–707.[CrossRef][Medline]
57. Treu EB, de Slegte RG, Golding RP, Sperber M, van Zanten TE, Valk J. CT findings in paravertebral synovial sarcoma. J Comput Assist Tomogr 1986;10:460–462.[Medline]
58. Fanney D, Castillo M, Lerner HH. Computed tomography of calcified synovial sarcoma of the hypopharynx. J Comput Assist Tomogr 1988;12: 687–689.[Medline]
59. Valenzuela RF, Kim EE, Seo JG, Patel S, Yasko AW. A revisit of MRI analysis for synovial sarcoma. Clin Imaging 2000;24:231–235.[CrossRef][Medline]
60. Hirsch RJ, Yousem DM, Loevner LA, et al. Synovial sarcomas of the head and neck: MR findings. AJR Am J Roentgenol 1997;169:1185–1188.[Abstract/Free Full Text]
61. Sigal R, Chancelier MD, Luboinski B, Shapeero LG, Bosq J, Vanel D. Synovial sarcomas of the head and neck: CT and MR findings. AJNR Am J Neuroradiol 1992;13:1459–1462.[Abstract]
62. Bernreuter WK, Sartoris DJ, Resnick D. Magnetic resonance imaging of synovial sarcoma. J Foot Surg 1990;29:94–100.[Medline]
63. Mahajan H, Lorigan JG, Shirkhoda A. Synovial sarcoma: MR imaging. Magn Reson Imaging 1989;7:211–216.[CrossRef][Medline]
64. Morton MJ, Berquist TH, McLeod RA, Unni KK, Sim FH. MR imaging of synovial sarcoma. AJR Am J Roentgenol 1991;156:337–340.[Abstract/Free Full Text]
65. Blacksin MF, Siegel JR, Benevenia J, Aisner SC. Synovial sarcoma: frequency of nonaggressive MR characteristics. J Comput Assist Tomogr 1997;21: 785–789.[CrossRef][Medline]
66. van Rijswijk CS, Hogendoorn PC, Taminiau AH, Bloem JL. Synovial sarcoma: dynamic contrast-enhanced MR imaging features. Skeletal Radiol 2001;30:25–30.[CrossRef][Medline]
67. de Silva MV, McMahon AD, Reid R. Prognostic factors associated with local recurrence, metastases, and tumor-related death in patients with synovial sarcoma. Am J Clin Oncol 2004;27:113–121.[CrossRef][Medline]
68. Frustaci S, Gherlinzoni F, De Paoli A, et al. Adjuvant chemotherapy for adult soft tissue sarcomas of the extremities and girdles: results of the Italian randomized cooperative trial. J Clin Oncol 2001; 19:1238–1247.[Abstract/Free Full Text]
69. Grobmyer SR, Maki RG, Demetri GD, et al. Neo-adjuvant chemotherapy for primary high-grade extremity soft tissue sarcoma. Ann Oncol 2004;15: 1667–1672.[Abstract/Free Full Text]
70. Kraybill WG, Harris J, Spiro IJ, et al. Phase II study of neoadjuvant chemotherapy and radiation therapy in the management of high-risk, high-grade, soft tissue sarcomas of the extremities and body wall: Radiation Therapy Oncology Group Trial 9514. J Clin Oncol 2006;24:619–625.[Abstract/Free Full Text]
71. Andrassy RJ, Okcu MF, Despa S, Raney RB. Synovial sarcoma in children: surgical lessons from a single institution and review of the literature. J Am Coll Surg 2001;192:305–313.[CrossRef][Medline]
72. Ruka W, Rutkowski P, Falkowski S, Morysinski T, Nowecki ZI. Aggressive combined treatment of synovial sarcoma patients without distant metastases: single-center experience [abstract]. J Clin Oncol, 2004 ASCO Annual Meeting Proceedings (Post-Meeting Edition) 2004;22:818.
73. Eilber FC, Eilber FR, Eckardt JJ, et al. Impact of ifosfamide-based chemotherapy on survival in patients with primary extremity synovial sarcoma [abstract]. J Clin Oncol, 2004 ASCO Annual Meeting Proceedings (Post-Meeting Edition) 2004;22:818.
74. Kuklo TR, Temple HT, Owens BD, et al. Preoperative versus postoperative radiation therapy for soft-tissue sarcomas. Am J Orthop 2005;34:75–80.[CrossRef][Medline]
75. Virkus WW, Mollabashy A, Reith JD, Zlotecki RA, Berrey BH, Scarborough MT. Preoperative radiotherapy in the treatment of soft tissue sarcomas. Clin Orthop Relat Res 2002;397:177–189.
76. Mullen JR, Zagars GK. Synovial sarcoma outcome following conservation surgery and radiotherapy. Radiother Oncol 1994;33:23–30.[CrossRef][Medline]
77. Paulino AC. Synovial sarcoma prognostic factors and patterns of failure. Am J Clin Oncol 2004;27: 122–127.[CrossRef][Medline]
78. Ryan JR, Baker LH, Benjamin RS. The natural history of metastatic synovial sarcoma: experience of the Southwest Oncology group. Clin Orthop Relat Res 1982;164:257–260.
79. Oda Y, Hashimoto H, Tsuneyoshi M, Takeshita S. Survival in synovial sarcoma: a multivariate study of prognostic factors with special emphasis on the comparison between early death and long-term survival. Am J Surg Pathol 1993;17:35–44.[Medline]
80. Raney RB. Synovial sarcoma in young people: background, prognostic factors, and therapeutic questions. J Pediatr Hematol Oncol 2005;27:207–211.[CrossRef][Medline]
81. Varela-Duran J, Enzinger FM. Calcifying synovial sarcoma. Cancer 1982;50:345–352.[CrossRef][Medline]
82. Evans HL. Synovial sarcoma: a study of 23 biphasic and 17 probable monophasic examples. Pathol Annu 1980;15:309–331.[Medline]
83. Cagle LA, Mirra JM, Storm FK, Roe DJ, Eilber FR. Histologic features relating to prognosis in synovial sarcoma. Cancer 1987;59:1810–1814.[CrossRef][Medline]
84. Skytting B, Meis-Kindblom JM, Larsson O, et al. Synovial sarcoma: identification of favorable and unfavorable histologic types—a Scandinavian sarcoma group study of 104 cases. Acta Orthop Scand 1999;70:543–554.[Medline]
85. Singer S, Baldini EH, Demetri GD, Fletcher JA, Corson JM. Synovial sarcoma: prognostic significance of tumor size, margin of resection, and mitotic activity for survival. J Clin Oncol 1996;14: 1201–1208.[Abstract/Free Full Text]
86. Nilsson G, Skytting B, Xie Y, et al. The SYT-SSX1 variant of synovial sarcoma is associated with a high rate of tumor cell proliferation and poor clinical outcome. Cancer Res 1999;59:3180–3184.[Abstract/Free Full Text]
87. Kawai A, Woodruff J, Healey JH, Brennan MF, Antonescu CR, Ladanyi M. SYT-SSX gene fusion as a determinant of morphology and prognosis in synovial sarcoma. N Engl J Med 1998;338:153–160.[Abstract/Free Full Text]

This Article Abstract Figures Only Full Text (PDF) CME Test (opens in a new window) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Murphey, M. D. Articles by Gajewski, D. A. Search for Related Content PubMed PubMed Citation Articles by Murphey, M. D. Articles by Gajewski, D. A. Related Collections Musculoskeletal Radiology Oncologic Imaging