DOI: 10.1148/rg.235035134
(Radiographics. 2003;23:1245-1278.)
From the Archives of the AFIP
Imaging of Primary Chondrosarcoma: Radiologic-Pathologic Correlation1
Mark D. Murphey, MD,
Eric A. Walker, MD,
Anthony J. Wilson, MB, ChB,
Mark J. Kransdorf, MD,
H. Thomas Temple, MD and
Francis H. Gannon, MD
1 From the Departments of Radiologic Pathology (M.D.M., E.A.W., A.J.W.) and Orthopedic Pathology (F.H.G.), Armed Forces Institute of Pathology, 6825 16th Street NW, Bldg 54, Rm M-133A, Washington, DC 20306; Departments of Radiology and Nuclear Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md (M.D.M.); Department of Radiology, University of Maryland School of Medicine, Baltimore (M.D.M.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.J.W.); Department of Radiology, Mayo Clinic, Jacksonville, Fla (M.J.K.); and Department of Orthopedic Surgery, University of Miami School of Medicine, Miami, Fla (H.T.T.). Received May 19, 2003; revision requested June 10 and received June 20; accepted June 23. Address correspondence to M.D.M. (e-mail: murphey@afip.osd.mil).
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Abstract
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Chondrosarcoma is a malignant tumor that produces cartilage matrix, and lesions that arise de novo are called primary. Primary chondrosarcoma is the third most common primary malignant tumor of bone, constituting 20%–27% of all primary malignant osseous neoplasms. There are numerous types of primary chondrosarcomas, including conventional intramedullary, clear cell, juxtacortical, myxoid, mesenchymal, extraskeletal, and dedifferentiated. The conventional intramedullary chondrosarcoma is the most frequent type, and it most commonly involves the long bones or pelvis in up to 65% of cases. Although the pathologic appearance varies with specific lesion type, chondrosarcomas grow with lobular type architecture, and these hyaline cartilage nodules demonstrate high water content and peripheral enchondral ossification. Imaging features directly reflect this pathologic appearance, and the various subtypes often show distinctive features. Radiographic findings often suggest the diagnosis of chondrosarcoma because of identification of typical "ring-and-arc" chondroid matrix mineralization (representing the enchondral ossification) and aggressive features of deep endosteal scalloping and soft-tissue extension. These latter features are usually best assessed, as is lesion staging, with computed tomography (CT) or magnetic resonance (MR) imaging. CT is optimal to detect the matrix mineralization, particularly when it is subtle or when the lesion is located in anatomically complex areas. Both CT and MR imaging depict the high water content of these lesions as low attenuation and very high signal intensity with T2-weighting, respectively. Understanding and recognizing the spectrum of appearances of the various types of primary chondrosarcoma allow improved patient assessment and are vital for optimal clinical management including diagnosis, biopsy, staging, treatment, and prognosis.
Index Terms: Bone neoplasms, 40.321 • Bone neoplasms, CT, 40.1211 • Bone neoplasms, MR, 40.12141 • Sarcoma, 40.321
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LEARNING OBJECTIVES FOR TEST 6
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After reading this article and taking the test, the reader will be able to:
- List the radiologic spectrum of primary chondrosarcoma.
- Describe the pathologic basis of the radiologic features of primary chondrosarcoma.
- Recognize the radiologic manifestations that may allow differentiation of the various types of primary chondrosarcoma.
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Introduction
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Chondrosarcoma is a malignant tumor with cells that produce cartilage matrix. Chondrosarcomas that arise de novo are called primary chondrosarcomas. Conversely, chondrosarcomas superimposed on preexisting benign cartilaginous neoplasms such as enchondroma or osteochondroma are referred to as secondary chondrosarcomas. Chondrosarcomas are also categorized as central, peripheral, or juxtacortical (periosteal) lesions depending on their osseous location. Central chondrosarcomas are intramedullary in origin, although large tumors may erode the cortex and invade the surrounding soft tissue. Peripheral chondrosarcomas are subdivided into those secondary to a preexisting osteochondroma and those developing from the bone surface (juxtacortical).
Chondrosarcoma is the third most common primary malignant tumor of bone, exceeded in frequency only by multiple myeloma and osteosarcoma. Chondrosarcoma accounts for 3.5% of all primary bone tumors that lead to biopsy and 20%–27% of primary malignant osseous neoplasms (1–7).
Numerous categories (incorporating both location and histologic characteristics) of primary chondrosarcomas have been described, including conventional intramedullary, clear cell, juxtacortical, myxoid, mesenchymal, extraskeletal, and dedifferentiated. Radiographic findings often strongly suggest the diagnosis of chondrosarcoma by demonstrating a lesion with typical chondroid matrix mineralization (ring-and-arc pattern) and aggressive growth features. Additional imaging modalities including bone scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging are frequently employed to evaluate these neoplasms further and for purposes of staging and guiding surgical resection. In this article, the clinical characteristics, pathologic features, various radiologic appearances, and treatment and prognosis for the different types of primary chondrosarcoma are discussed and illustrated.
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Pathologic Features
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Conventional Intramedullary Chondrosarcoma
At gross pathologic evaluation, conventional intramedullary chondrosarcomas are large lesions, the majority being greater than 4 cm in size (1–7). In fact, in one study, 50% of chondrosarcomas were greater than 10 cm in size, occupying from 30% to more than 50% of the bone length (Fig 1) (8). These hyaline cartilage neoplasms typically grow with a lobular architecture (Figs 1, 2). This growth pattern frequently causes lobular, deep, endosteal scalloping that may result in focal areas of cortical penetration and associated soft-tissue extension. Nonmineralized regions have a translucent appearance, reflecting the high water content of hyaline cartilage, particularly in low-grade lesions. Areas with matrix mineralization (calcification) appear granular and gritty in consistency.
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Figure 1. Photograph of a coronally sectioned gross specimen of a conventional intramedullary chondrosarcoma of the femur demonstrates a multilobulated lesion replacing a long extent of the marrow space (C). Two foci of deep endosteal scalloping (greater than two-thirds of the normal cortical thickness) with expansile remodeling of bone (arrows) are seen. A biopsy site is noted at the superolateral diaphysis (B).
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Figure 2. Photograph of an axially sectioned whole-mounted specimen (hematoxylin-eosin stain) shows multiple cartilaginous lobules (*) replacing the femoral marrow with deep endosteal scalloping anteriorly, cortical penetration, and a small focus of soft-tissue extension (large arrows), findings that represent conventional intramedullary chondrosarcoma. Enchondral ossification at the periphery of the chondroid lobules causing a ring-and-arc appearance is also seen (small arrows).
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Histologic examination reveals lobules of hyaline cartilage (Figs 1, 2). The areas of matrix mineralization associated with conventional intramedullary chondrosarcoma have a distinctive ring-and-arc–like pattern. This pattern reflects enchondral ossification around lobules of well-formed hyaline cartilage (Fig 2). Higher-grade chondrosarcomas have larger areas that are not calcified. The nonmineralized tissue in chondrosarcoma has high water content, varying histologically from mature hyaline cartilage to a more myxoid stroma. The single most important feature distinguishing conventional intramedullary chondrosarcoma from enchondroma is the relationship of the chondroid tissue to the surrounding bone (2,3). Entrapment and destruction of the surrounding trabecular bone is the hallmark of a chondrosarcoma and should be identified before conclusively making this diagnosis (Fig 3). Sections taken at the edge of conventional intramedullary chondrosarcoma best demonstrate cartilage invading the marrow between trabecular bone (1–5). Once this morphologic feature has been identified, the degree of cellularity is used to determine grading (see later discussion). Most of the host bone is resorbed, but partially replaced trabeculae may become completely surrounded by proliferating cartilage, remaining as islands of normal bone within the neoplasm. Invasion and resorption of the cortex, beginning with the endosteal surface, occur as the first step in extraosseous extension.
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Figure 3. High-power photomicrograph (original magnification, x200; hematoxylin-eosin stain) shows a grade 2 conventional chondrosarcoma with cartilage lobules (C) entrapping osseous trabeculae (T) and cellular atypia represented by multinucleated cartilage cells (arrows).
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The broad microscopic spectrum seen with conventional intramedullary chondrosarcomas lends itself to histologic grading and correlates with the clinical behavior of these lesions and their ultimate prognosis. A three-grade system is commonly used, although some institutions employ a four-grade scheme. Grade 1 lesions (low grade) have chondrocytes with small dense nuclei, although some slightly enlarged nuclei (>8 µm) and a few multinucleated cells (most commonly binucleated) are present (1–5). The stroma is predominantly chondroid. Myxoid areas are usually sparse or absent. Distinction of grade 1 chondrosarcoma from enchondroma is often difficult.
Grade 2 chondrosarcomas (intermediate grade) have less chondroid matrix and are correspondingly more cellular (Fig 3). This increased cellularity is particularly prominent at the periphery of tumor lobules, where chondroid matrix may be completely absent and rare mitotic figures may be found (1–12). The chondrocyte nuclei in the center of the lobules are enlarged and either vesicular or hyperchromatic. Binucleated and multinucleated chondrocytes are common. Necrosis ranges from small microscopic foci to completely necrotic lobules. The stroma is frequently myxoid.
Grade 3 chondrosarcomas (high grade) exhibit greater cellularity and nuclear pleomorphism than grade 2 tumors (1–12). Chondroid matrix is sparse or absent, and the small amount of intercellular material present is often myxoid. The neoplastic chondrocytes are frequently arranged in cords and clumps. Individual cells commonly have stellate or markedly irregular shapes. Foci of necrosis are almost invariably seen and are frequently extensive. Nuclei are typically vesicular, are often spindle shaped, and may be five to 10 times larger than normal.
Clear Cell Chondrosarcoma
Clear cell chondrosarcoma is a rare low-grade malignant cartilaginous tumor. At histologic analysis, these lesions reveal numerous cells with abundant clear, vacuolated cytoplasm containing large amounts of glycogen (clear cell chondrocytes) that often lie between heavily calcified trabeculae of cartilage matrix and may superficially resemble bone (Fig 4). Areas of osseous metaplasia may also be prominent, bearing a striking resemblance to osteoblastoma. Unlike conventional chondrosarcoma, clear cell chondrosarcomas frequently contain large areas of hemorrhage and cyst formation. Areas of conventional chondrosarcoma are apparent in approximately 50% of clear cell chondrosarcomas (1–6).
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Figure 4. High-power photomicrograph (original magnification, x250; hematoxylin-eosin stain) shows large cells with abundant clear cytoplasm (*) secondary to high glycogen content and prominent nucleoli within the nucleus, findings typical of a clear cell chondrosarcoma. Areas of typical conventional chondrosarcoma were also seen (not shown).
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Juxtacortical Chondrosarcoma
At gross pathologic examination, juxtacortical chondrosarcoma arises on the surface of bone and is covered by a fibrous pseudocapsule that is continuous with the underlying periosteum (Fig 5). Cortical erosion is often present. Although medullary involvement is unusual, it has been reported. These lesions are histologically identical to conventional intramedullary chondrosarcoma with a variable degree of enchondral bone formation (1–7).
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Figure 5. Photograph of an oblique longitudinally sectioned gross specimen from the left calf of a 37-year-old man with a juxtacortical chondrosarcoma shows typical lobular chondroid architecture (C) with extrinsic erosion of the fibula (arrows) and cortical thickening (P). The marrow canal is not involved (M). (For radiologic images see Fig 15.)
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Myxoid Chondrosarcoma
Myxoid chondrosarcoma is a rare histologic variant of chondrosarcoma that occurs in both bone and soft tissue and is considered an intermediate-grade tumor. These lesions have marked high water content, related to the extensive myxoid stroma and better-differentiated areas of hyaline cartilage (Fig 6). Cellular areas are arranged in cords, resembling chordoma from which they can be difficult to differentiate (Fig 6) (4).
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Figure 6a. Myxoid chondrosarcomas in two different patients. (a) Photograph of a sagittally sectioned gross specimen of an amputated finger shows gelatinous consistency of the myxoid tissue (*) and small foci of cartilage (C). (b) Photomicrograph (original magnification, x175; hematoxylin-eosin stain) reveals a cartilage neoplasm with prominent myxoid changes and cordlike arrangement of cells surrounding osseous trabeculae (T).
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Figure 6b. Myxoid chondrosarcomas in two different patients. (a) Photograph of a sagittally sectioned gross specimen of an amputated finger shows gelatinous consistency of the myxoid tissue (*) and small foci of cartilage (C). (b) Photomicrograph (original magnification, x175; hematoxylin-eosin stain) reveals a cartilage neoplasm with prominent myxoid changes and cordlike arrangement of cells surrounding osseous trabeculae (T).
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Mesenchymal Chondrosarcoma
These high-grade malignant cartilaginous tumors are rare and can originate in either bone or soft tissue. The characteristic histologic feature is a bimorphic pattern. Large components of the tumor are composed of small, uniform, round to spindle-shaped cells, which resemble those of Ewing sarcoma. These cellular areas also demonstrate a perivascular arrangement that results in a hemangiopericytoma-like pattern (Fig 7). However, their characteristic focal admixed areas of limited or extensive malignant cartilaginous tissue arranged in a lobular pattern allows for accurate pathologic diagnosis (1–7).
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Figure 7. Photomicrograph (original magnification, x150; hematoxylin-eosin stain) shows the typical bimorphic appearance of mesenchymal chondrosarcoma, with a malignant cartilaginous component on the right (C) and an abrupt transition to a more cellular vascular portion on the left (H) with hemangiopericytoma-like features. Arrows = vascular channels.
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Dedifferentiated Chondrosarcoma
This cartilaginous malignancy is characterized by conventional low-grade chondrosarcoma with abrupt transition to foci that have dedifferentiated into a higher-grade, more aggressive component. The noncartilaginous component may be either small or extensive and is most frequently malignant fibrous histiocytoma, osteosarcoma, or fibrosarcoma (Fig 8) (1–7). Rhabdomyosarcoma, leiomyosarcoma, and angiosarcoma have also been reported as the dedifferentiated component. The cartilaginous and noncartilaginous components are often adjacent, and the term collision of two tumors has been applied to this lesion (1).
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Figure 8. Photomicrograph (original magnification, x200; hematoxylin-eosin stain) shows a "collision of two tumors" typical of a dedifferentiated chondrosarcoma, with low-grade chondrosarcoma on the right (C) adjacent to a high-grade fibrosarcoma component on the left (F) with an abrupt transition.
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Clinical Characteristics and Imaging Features
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Conventional Intramedullary Chondrosarcoma
Conventional intramedullary chondrosarcoma is the most common type of primary chondrosarcoma. It has also been referred to as central chondrosarcoma. Patients with conventional chondrosarcoma most commonly present in the 4th to 5th decades of life. There is a male predilection of 1.5–2 to 1. Clinical symptoms are nonspecific, with pain being the most frequent symptom, occurring in at least 95% of patients (2,13). The pain is often insidious, progressive, and worse at night and has been present for months to years before the time of presentation. A palpable soft-tissue mass or fullness has also been described in 28%–82% of patients (1–7,13). Pathologic fractures are also common at initial presentation in 3%–17% of patients with conventional chondrosarcoma (1–17).
The most common skeletal location for conventional chondrosarcoma is the long tubular bones (which are also a common site for solitary enchondroma), accounting for approximately 45% of cases (Figs 9, 10) (1–21). The femur is the single most commonly affected long bone, representing approximately 20%–35% of cases, followed in frequency by the tibia (5%) (1–21). The upper extremity is involved in 10%–20% of cases, with the proximal humerus being the most frequent site (1–21). The axial skeleton is also commonly affected, with the innominate bone (Fig 11) accounting for 25% of cases and the ribs 8% (Fig 12) (1–3). Other less frequently involved sites are the spine (7% of cases), scapula (5%), and sternum (2%) (1–10). Chondrosarcoma can involve any bone, and rarely affected locations include the craniofacial region (Fig 13), neck (arising from the hyoid as well as laryngeal and tracheal cartilage), forearm, clavicle, sesamoids (including the patella), and the short tubular bones of the hands and feet (1%–4% of all cases) (1–3). Fibular origin has also been reported as rare, but this has not been our experience (7% of long bone lesions) (13). Long tubular bone lesions most commonly involve the metaphysis (49% of cases), followed by the diaphysis (36%) (13). Conventional chondrosarcomas centered in the epiphysis are unusual, accounting for only 16% of cases (13). In contrast, solitary epiphyseal enchondromas are rare. Chondrosarcomas involving the humerus and fibula are almost invariably proximal. Similarly, lesions in the femur and tibia are more common proximally.
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Figure 9a. Conventional intramedullary chondrosarcoma of the humerus in a 21-year-old man with shoulder pain. (a) Anteroposterior shoulder radiograph shows a proximal humeral mixed lytic and sclerotic lesion with expansile remodeling. The sclerotic component represents typical chondroid ring-and-arc calcification (white arrows). Lytic focus seen inferolaterally (black arrow) demonstrates deep endosteal scalloping typical of chondrosarcoma. (b) Anterior bone scan shows that the lesion has radionuclide uptake greater than that in the anterior iliac spines. (c) Axial CT scan shows decreased attenuation of the nonmineralized component of the lesion and chondroid mineralization (arrows). (d, e) Axial T1-weighted fat saturation (repetition time msec/echo time msec = 600/20) MR images obtained before (d) and after (e) intravenous administration of gadolinium show signal intensity similar to that of muscle and mild peripheral and septal enhancement (arrows). (f) Coronal T2-weighted (3,000/57) MR image demonstrates lobular growth (large arrow) and a focus of deep endosteal scalloping with cortical penetration (small arrows) laterally. (g) Photograph of the coronally sectioned gross specimen shows a cartilage lesion with lobular growth (large arrow) and cortical destruction laterally (small arrows), identically correlating to imaging features.
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Figure 9b. Conventional intramedullary chondrosarcoma of the humerus in a 21-year-old man with shoulder pain. (a) Anteroposterior shoulder radiograph shows a proximal humeral mixed lytic and sclerotic lesion with expansile remodeling. The sclerotic component represents typical chondroid ring-and-arc calcification (white arrows). Lytic focus seen inferolaterally (black arrow) demonstrates deep endosteal scalloping typical of chondrosarcoma. (b) Anterior bone scan shows that the lesion has radionuclide uptake greater than that in the anterior iliac spines. (c) Axial CT scan shows decreased attenuation of the nonmineralized component of the lesion and chondroid mineralization (arrows). (d, e) Axial T1-weighted fat saturation (repetition time msec/echo time msec = 600/20) MR images obtained before (d) and after (e) intravenous administration of gadolinium show signal intensity similar to that of muscle and mild peripheral and septal enhancement (arrows). (f) Coronal T2-weighted (3,000/57) MR image demonstrates lobular growth (large arrow) and a focus of deep endosteal scalloping with cortical penetration (small arrows) laterally. (g) Photograph of the coronally sectioned gross specimen shows a cartilage lesion with lobular growth (large arrow) and cortical destruction laterally (small arrows), identically correlating to imaging features.
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Figure 9c. Conventional intramedullary chondrosarcoma of the humerus in a 21-year-old man with shoulder pain. (a) Anteroposterior shoulder radiograph shows a proximal humeral mixed lytic and sclerotic lesion with expansile remodeling. The sclerotic component represents typical chondroid ring-and-arc calcification (white arrows). Lytic focus seen inferolaterally (black arrow) demonstrates deep endosteal scalloping typical of chondrosarcoma. (b) Anterior bone scan shows that the lesion has radionuclide uptake greater than that in the anterior iliac spines. (c) Axial CT scan shows decreased attenuation of the nonmineralized component of the lesion and chondroid mineralization (arrows). (d, e) Axial T1-weighted fat saturation (repetition time msec/echo time msec = 600/20) MR images obtained before (d) and after (e) intravenous administration of gadolinium show signal intensity similar to that of muscle and mild peripheral and septal enhancement (arrows). (f) Coronal T2-weighted (3,000/57) MR image demonstrates lobular growth (large arrow) and a focus of deep endosteal scalloping with cortical penetration (small arrows) laterally. (g) Photograph of the coronally sectioned gross specimen shows a cartilage lesion with lobular growth (large arrow) and cortical destruction laterally (small arrows), identically correlating to imaging features.
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Figure 9d. Conventional intramedullary chondrosarcoma of the humerus in a 21-year-old man with shoulder pain. (a) Anteroposterior shoulder radiograph shows a proximal humeral mixed lytic and sclerotic lesion with expansile remodeling. The sclerotic component represents typical chondroid ring-and-arc calcification (white arrows). Lytic focus seen inferolaterally (black arrow) demonstrates deep endosteal scalloping typical of chondrosarcoma. (b) Anterior bone scan shows that the lesion has radionuclide uptake greater than that in the anterior iliac spines. (c) Axial CT scan shows decreased attenuation of the nonmineralized component of the lesion and chondroid mineralization (arrows). (d, e) Axial T1-weighted fat saturation (repetition time msec/echo time msec = 600/20) MR images obtained before (d) and after (e) intravenous administration of gadolinium show signal intensity similar to that of muscle and mild peripheral and septal enhancement (arrows). (f) Coronal T2-weighted (3,000/57) MR image demonstrates lobular growth (large arrow) and a focus of deep endosteal scalloping with cortical penetration (small arrows) laterally. (g) Photograph of the coronally sectioned gross specimen shows a cartilage lesion with lobular growth (large arrow) and cortical destruction laterally (small arrows), identically correlating to imaging features.
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Figure 9e. Conventional intramedullary chondrosarcoma of the humerus in a 21-year-old man with shoulder pain. (a) Anteroposterior shoulder radiograph shows a proximal humeral mixed lytic and sclerotic lesion with expansile remodeling. The sclerotic component represents typical chondroid ring-and-arc calcification (white arrows). Lytic focus seen inferolaterally (black arrow) demonstrates deep endosteal scalloping typical of chondrosarcoma. (b) Anterior bone scan shows that the lesion has radionuclide uptake greater than that in the anterior iliac spines. (c) Axial CT scan shows decreased attenuation of the nonmineralized component of the lesion and chondroid mineralization (arrows). (d, e) Axial T1-weighted fat saturation (repetition time msec/echo time msec = 600/20) MR images obtained before (d) and after (e) intravenous administration of gadolinium show signal intensity similar to that of muscle and mild peripheral and septal enhancement (arrows). (f) Coronal T2-weighted (3,000/57) MR image demonstrates lobular growth (large arrow) and a focus of deep endosteal scalloping with cortical penetration (small arrows) laterally. (g) Photograph of the coronally sectioned gross specimen shows a cartilage lesion with lobular growth (large arrow) and cortical destruction laterally (small arrows), identically correlating to imaging features.
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Figure 9f. Conventional intramedullary chondrosarcoma of the humerus in a 21-year-old man with shoulder pain. (a) Anteroposterior shoulder radiograph shows a proximal humeral mixed lytic and sclerotic lesion with expansile remodeling. The sclerotic component represents typical chondroid ring-and-arc calcification (white arrows). Lytic focus seen inferolaterally (black arrow) demonstrates deep endosteal scalloping typical of chondrosarcoma. (b) Anterior bone scan shows that the lesion has radionuclide uptake greater than that in the anterior iliac spines. (c) Axial CT scan shows decreased attenuation of the nonmineralized component of the lesion and chondroid mineralization (arrows). (d, e) Axial T1-weighted fat saturation (repetition time msec/echo time msec = 600/20) MR images obtained before (d) and after (e) intravenous administration of gadolinium show signal intensity similar to that of muscle and mild peripheral and septal enhancement (arrows). (f) Coronal T2-weighted (3,000/57) MR image demonstrates lobular growth (large arrow) and a focus of deep endosteal scalloping with cortical penetration (small arrows) laterally. (g) Photograph of the coronally sectioned gross specimen shows a cartilage lesion with lobular growth (large arrow) and cortical destruction laterally (small arrows), identically correlating to imaging features.
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Figure 9g. Conventional intramedullary chondrosarcoma of the humerus in a 21-year-old man with shoulder pain. (a) Anteroposterior shoulder radiograph shows a proximal humeral mixed lytic and sclerotic lesion with expansile remodeling. The sclerotic component represents typical chondroid ring-and-arc calcification (white arrows). Lytic focus seen inferolaterally (black arrow) demonstrates deep endosteal scalloping typical of chondrosarcoma. (b) Anterior bone scan shows that the lesion has radionuclide uptake greater than that in the anterior iliac spines. (c) Axial CT scan shows decreased attenuation of the nonmineralized component of the lesion and chondroid mineralization (arrows). (d, e) Axial T1-weighted fat saturation (repetition time msec/echo time msec = 600/20) MR images obtained before (d) and after (e) intravenous administration of gadolinium show signal intensity similar to that of muscle and mild peripheral and septal enhancement (arrows). (f) Coronal T2-weighted (3,000/57) MR image demonstrates lobular growth (large arrow) and a focus of deep endosteal scalloping with cortical penetration (small arrows) laterally. (g) Photograph of the coronally sectioned gross specimen shows a cartilage lesion with lobular growth (large arrow) and cortical destruction laterally (small arrows), identically correlating to imaging features.
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Figure 10a. Conventional intramedullary chondrosarcoma of the tibia in a 60-year-old man. (a) Anteroposterior and lateral radiographs show an extensive diaphyseal tibial lesion that is predominantly lytic. Areas of chondroid matrix mineralization are seen superiorly (large arrow) and a focus of deep scalloping (small arrows), cortical remodeling, and periosteal reaction (arrowheads) anterolaterally. (b) Anterior bone scan reveals marked radionuclide uptake in the lesion greater than that in the anterior iliac spines. (c) Axial CT scan shows the deep endosteal scalloping, cortical breakthrough, soft-tissue extension (M), and central flocculent calcification (C). The nonmineralized component has low attenuation. (d) Axial gadolinium-enhanced T1-weighted (688/14) MR image with fat saturation reveals mild peripheral enhancement (arrows) with deep endosteal scalloping extending through the cortex with soft-tissue extension (M). (e) Coronal T2-weighted (3,426/60) fat saturation MR image shows lobular growth (arrows), cortical penetration with soft-tissue extension (M), and high signal intensity throughout the lesion. (f) Photograph of the coronally sectioned gross specimen reveals the deep endosteal scalloping (arrows) and soft-tissue extension (M), identically correlating to imaging features.
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Figure 10b. Conventional intramedullary chondrosarcoma of the tibia in a 60-year-old man. (a) Anteroposterior and lateral radiographs show an extensive diaphyseal tibial lesion that is predominantly lytic. Areas of chondroid matrix mineralization are seen superiorly (large arrow) and a focus of deep scalloping (small arrows), cortical remodeling, and periosteal reaction (arrowheads) anterolaterally. (b) Anterior bone scan reveals marked radionuclide uptake in the lesion greater than that in the anterior iliac spines. (c) Axial CT scan shows the deep endosteal scalloping, cortical breakthrough, soft-tissue extension (M), and central flocculent calcification (C). The nonmineralized component has low attenuation. (d) Axial gadolinium-enhanced T1-weighted (688/14) MR image with fat saturation reveals mild peripheral enhancement (arrows) with deep endosteal scalloping extending through the cortex with soft-tissue extension (M). (e) Coronal T2-weighted (3,426/60) fat saturation MR image shows lobular growth (arrows), cortical penetration with soft-tissue extension (M), and high signal intensity throughout the lesion. (f) Photograph of the coronally sectioned gross specimen reveals the deep endosteal scalloping (arrows) and soft-tissue extension (M), identically correlating to imaging features.
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Figure 10c. Conventional intramedullary chondrosarcoma of the tibia in a 60-year-old man. (a) Anteroposterior and lateral radiographs show an extensive diaphyseal tibial lesion that is predominantly lytic. Areas of chondroid matrix mineralization are seen superiorly (large arrow) and a focus of deep scalloping (small arrows), cortical remodeling, and periosteal reaction (arrowheads) anterolaterally. (b) Anterior bone scan reveals marked radionuclide uptake in the lesion greater than that in the anterior iliac spines. (c) Axial CT scan shows the deep endosteal scalloping, cortical breakthrough, soft-tissue extension (M), and central flocculent calcification (C). The nonmineralized component has low attenuation. (d) Axial gadolinium-enhanced T1-weighted (688/14) MR image with fat saturation reveals mild peripheral enhancement (arrows) with deep endosteal scalloping extending through the cortex with soft-tissue extension (M). (e) Coronal T2-weighted (3,426/60) fat saturation MR image shows lobular growth (arrows), cortical penetration with soft-tissue extension (M), and high signal intensity throughout the lesion. (f) Photograph of the coronally sectioned gross specimen reveals the deep endosteal scalloping (arrows) and soft-tissue extension (M), identically correlating to imaging features.
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Figure 10d. Conventional intramedullary chondrosarcoma of the tibia in a 60-year-old man. (a) Anteroposterior and lateral radiographs show an extensive diaphyseal tibial lesion that is predominantly lytic. Areas of chondroid matrix mineralization are seen superiorly (large arrow) and a focus of deep scalloping (small arrows), cortical remodeling, and periosteal reaction (arrowheads) anterolaterally. (b) Anterior bone scan reveals marked radionuclide uptake in the lesion greater than that in the anterior iliac spines. (c) Axial CT scan shows the deep endosteal scalloping, cortical breakthrough, soft-tissue extension (M), and central flocculent calcification (C). The nonmineralized component has low attenuation. (d) Axial gadolinium-enhanced T1-weighted (688/14) MR image with fat saturation reveals mild peripheral enhancement (arrows) with deep endosteal scalloping extending through the cortex with soft-tissue extension (M). (e) Coronal T2-weighted (3,426/60) fat saturation MR image shows lobular growth (arrows), cortical penetration with soft-tissue extension (M), and high signal intensity throughout the lesion. (f) Photograph of the coronally sectioned gross specimen reveals the deep endosteal scalloping (arrows) and soft-tissue extension (M), identically correlating to imaging features.
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Figure 10e. Conventional intramedullary chondrosarcoma of the tibia in a 60-year-old man. (a) Anteroposterior and lateral radiographs show an extensive diaphyseal tibial lesion that is predominantly lytic. Areas of chondroid matrix mineralization are seen superiorly (large arrow) and a focus of deep scalloping (small arrows), cortical remodeling, and periosteal reaction (arrowheads) anterolaterally. (b) Anterior bone scan reveals marked radionuclide uptake in the lesion greater than that in the anterior iliac spines. (c) Axial CT scan shows the deep endosteal scalloping, cortical breakthrough, soft-tissue extension (M), and central flocculent calcification (C). The nonmineralized component has low attenuation. (d) Axial gadolinium-enhanced T1-weighted (688/14) MR image with fat saturation reveals mild peripheral enhancement (arrows) with deep endosteal scalloping extending through the cortex with soft-tissue extension (M). (e) Coronal T2-weighted (3,426/60) fat saturation MR image shows lobular growth (arrows), cortical penetration with soft-tissue extension (M), and high signal intensity throughout the lesion. (f) Photograph of the coronally sectioned gross specimen reveals the deep endosteal scalloping (arrows) and soft-tissue extension (M), identically correlating to imaging features.
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Figure 10f. Conventional intramedullary chondrosarcoma of the tibia in a 60-year-old man. (a) Anteroposterior and lateral radiographs show an extensive diaphyseal tibial lesion that is predominantly lytic. Areas of chondroid matrix mineralization are seen superiorly (large arrow) and a focus of deep scalloping (small arrows), cortical remodeling, and periosteal reaction (arrowheads) anterolaterally. (b) Anterior bone scan reveals marked radionuclide uptake in the lesion greater than that in the anterior iliac spines. (c) Axial CT scan shows the deep endosteal scalloping, cortical breakthrough, soft-tissue extension (M), and central flocculent calcification (C). The nonmineralized component has low attenuation. (d) Axial gadolinium-enhanced T1-weighted (688/14) MR image with fat saturation reveals mild peripheral enhancement (arrows) with deep endosteal scalloping extending through the cortex with soft-tissue extension (M). (e) Coronal T2-weighted (3,426/60) fat saturation MR image shows lobular growth (arrows), cortical penetration with soft-tissue extension (M), and high signal intensity throughout the lesion. (f) Photograph of the coronally sectioned gross specimen reveals the deep endosteal scalloping (arrows) and soft-tissue extension (M), identically correlating to imaging features.
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Figure 11a. Conventional intramedullary chondrosarcoma of the acetabulum in a 52-year-old woman with a 2-year history of right hip and leg pain. (a) Anteroposterior hip radiograph shows subtle sclerosis caused by chondroid matrix mineralization and bone destruction of the ilium and iliopectoneal line cortex lesion center at the previous site of the triradiate cartilage (arrows). (b) Axial CT scan reveals an extensive low-attenuation soft-tissue mass (M) about the hip and faint intraosseous matrix mineralization (arrow). (c) Axial gadolinium-enhanced T1-weighted (666/10) MR image with fat saturation demonstrates peripheral and septal enhancement of both the soft-tissue and intraosseous components of the tumor (arrows) with hip joint invasion (arrowhead). (d) Coronal T2-weighted (3,300/102) MR image demonstrates soft-tissue extension (M) and high signal intensity similar to that of the bladder (B). (e) Photograph of the sagittally sectioned gross specimen demonstrates extensive marrow involvement (C), the soft-tissue mass (M), and joint invasion inferiorly (arrow).
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Figure 11b. Conventional intramedullary chondrosarcoma of the acetabulum in a 52-year-old woman with a 2-year history of right hip and leg pain. (a) Anteroposterior hip radiograph shows subtle sclerosis caused by chondroid matrix mineralization and bone destruction of the ilium and iliopectoneal line cortex lesion center at the previous site of the triradiate cartilage (arrows). (b) Axial CT scan reveals an extensive low-attenuation soft-tissue mass (M) about the hip and faint intraosseous matrix mineralization (arrow). (c) Axial gadolinium-enhanced T1-weighted (666/10) MR image with fat saturation demonstrates peripheral and septal enhancement of both the soft-tissue and intraosseous components of the tumor (arrows) with hip joint invasion (arrowhead). (d) Coronal T2-weighted (3,300/102) MR image demonstrates soft-tissue extension (M) and high signal intensity similar to that of the bladder (B). (e) Photograph of the sagittally sectioned gross specimen demonstrates extensive marrow involvement (C), the soft-tissue mass (M), and joint invasion inferiorly (arrow).
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Figure 11c. Conventional intramedullary chondrosarcoma of the acetabulum in a 52-year-old woman with a 2-year history of right hip and leg pain. (a) Anteroposterior hip radiograph shows subtle sclerosis caused by chondroid matrix mineralization and bone destruction of the ilium and iliopectoneal line cortex lesion center at the previous site of the triradiate cartilage (arrows). (b) Axial CT scan reveals an extensive low-attenuation soft-tissue mass (M) about the hip and faint intraosseous matrix mineralization (arrow). (c) Axial gadolinium-enhanced T1-weighted (666/10) MR image with fat saturation demonstrates peripheral and septal enhancement of both the soft-tissue and intraosseous components of the tumor (arrows) with hip joint invasion (arrowhead). (d) Coronal T2-weighted (3,300/102) MR image demonstrates soft-tissue extension (M) and high signal intensity similar to that of the bladder (B). (e) Photograph of the sagittally sectioned gross specimen demonstrates extensive marrow involvement (C), the soft-tissue mass (M), and joint invasion inferiorly (arrow).
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Figure 11d. Conventional intramedullary chondrosarcoma of the acetabulum in a 52-year-old woman with a 2-year history of right hip and leg pain. (a) Anteroposterior hip radiograph shows subtle sclerosis caused by chondroid matrix mineralization and bone destruction of the ilium and iliopectoneal line cortex lesion center at the previous site of the triradiate cartilage (arrows). (b) Axial CT scan reveals an extensive low-attenuation soft-tissue mass (M) about the hip and faint intraosseous matrix mineralization (arrow). (c) Axial gadolinium-enhanced T1-weighted (666/10) MR image with fat saturation demonstrates peripheral and septal enhancement of both the soft-tissue and intraosseous components of the tumor (arrows) with hip joint invasion (arrowhead). (d) Coronal T2-weighted (3,300/102) MR image demonstrates soft-tissue extension (M) and high signal intensity similar to that of the bladder (B). (e) Photograph of the sagittally sectioned gross specimen demonstrates extensive marrow involvement (C), the soft-tissue mass (M), and joint invasion inferiorly (arrow).
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Figure 11e. Conventional intramedullary chondrosarcoma of the acetabulum in a 52-year-old woman with a 2-year history of right hip and leg pain. (a) Anteroposterior hip radiograph shows subtle sclerosis caused by chondroid matrix mineralization and bone destruction of the ilium and iliopectoneal line cortex lesion center at the previous site of the triradiate cartilage (arrows). (b) Axial CT scan reveals an extensive low-attenuation soft-tissue mass (M) about the hip and faint intraosseous matrix mineralization (arrow). (c) Axial gadolinium-enhanced T1-weighted (666/10) MR image with fat saturation demonstrates peripheral and septal enhancement of both the soft-tissue and intraosseous components of the tumor (arrows) with hip joint invasion (arrowhead). (d) Coronal T2-weighted (3,300/102) MR image demonstrates soft-tissue extension (M) and high signal intensity similar to that of the bladder (B). (e) Photograph of the sagittally sectioned gross specimen demonstrates extensive marrow involvement (C), the soft-tissue mass (M), and joint invasion inferiorly (arrow).
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Figure 12a. Conventional chondrosarcoma of the rib in a 70-year-old man who presented with a painless anterior chest wall mass. (a) Lateral chest radiograph shows a mass (white arrows) overlying an anterior rib. Faint calcific opacity is seen (black arrow). (b) Axial CT scan demonstrates prominent chondroid matrix mineralization (arrows) to much better advantage and involvement of the costosternal junction. (c) Photograph of the axially sectioned gross specimen reveals the lesion clearly arising from the anterior rib and costal junction (R, arrows) and the lobular growth architecture (C) typical of hyaline cartilage neoplasms.
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Figure 12b. Conventional chondrosarcoma of the rib in a 70-year-old man who presented with a painless anterior chest wall mass. (a) Lateral chest radiograph shows a mass (white arrows) overlying an anterior rib. Faint calcific opacity is seen (black arrow). (b) Axial CT scan demonstrates prominent chondroid matrix mineralization (arrows) to much better advantage and involvement of the costosternal junction. (c) Photograph of the axially sectioned gross specimen reveals the lesion clearly arising from the anterior rib and costal junction (R, arrows) and the lobular growth architecture (C) typical of hyaline cartilage neoplasms.
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Figure 12c. Conventional chondrosarcoma of the rib in a 70-year-old man who presented with a painless anterior chest wall mass. (a) Lateral chest radiograph shows a mass (white arrows) overlying an anterior rib. Faint calcific opacity is seen (black arrow). (b) Axial CT scan demonstrates prominent chondroid matrix mineralization (arrows) to much better advantage and involvement of the costosternal junction. (c) Photograph of the axially sectioned gross specimen reveals the lesion clearly arising from the anterior rib and costal junction (R, arrows) and the lobular growth architecture (C) typical of hyaline cartilage neoplasms.
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Figure 13a. Craniofacial conventional chondrosarcoma in a 26-year-old man with nasal symptoms. (a) Coronal CT reformatted image reveals a low-attenuation mass (M) replacing nasal bones and displacing the nasal septum with small subtle chondroid matrix mineralization (arrows). (b, c) Sagittal T1-weighted (570/15) MR image obtained without (b) and coronal T1-weighted MR image (570/15) obtained with (c) gadolinium show the low-signal-intensity mass (M) with mild peripheral and septal enhancement (arrows) replacing the area of the cribriform plate in the anterior cranial skull base and extending into the nasal region. Severe sinus disease is seen. (d) Axial T2-weighted fat saturation (2,200/80) MR image shows that the mass (M) erodes the medial wall of the right maxillary sinus and left maxillary sinus with marked high signal intensity similar to that of mucosal thickening and fluid in both sinuses. Matrix mineralization cannot be seen. (e) Photograph of the gross specimen show portions of the cribriform plate superiorly, maxillary sinus, and lobules of cartilage growth (*).
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Figure 13b. Craniofacial conventional chondrosarcoma in a 26-year-old man with nasal symptoms. (a) Coronal CT reformatted image reveals a low-attenuation mass (M) replacing nasal bones and displacing the nasal septum with small subtle chondroid matrix mineralization (arrows). (b, c) Sagittal T1-weighted (570/15) MR image obtained without (b) and coronal T1-weighted MR image (570/15) obtained with (c) gadolinium show the low-signal-intensity mass (M) with mild peripheral and septal enhancement (arrows) replacing the area of the cribriform plate in the anterior cranial skull base and extending into the nasal region. Severe sinus disease is seen. (d) Axial T2-weighted fat saturation (2,200/80) MR image shows that the mass (M) erodes the medial wall of the right maxillary sinus and left maxillary sinus with marked high signal intensity similar to that of mucosal thickening and fluid in both sinuses. Matrix mineralization cannot be seen. (e) Photograph of the gross specimen show portions of the cribriform plate superiorly, maxillary sinus, and lobules of cartilage growth (*).
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Figure 13c. Craniofacial conventional chondrosarcoma in a 26-year-old man with nasal symptoms. (a) Coronal CT reformatted image reveals a low-attenuation mass (M) replacing nasal bones and displacing the nasal septum with small subtle chondroid matrix mineralization (arrows). (b, c) Sagittal T1-weighted (570/15) MR image obtained without (b) and coronal T1-weighted MR image (570/15) obtained with (c) gadolinium show the low-signal-intensity mass (M) with mild peripheral and septal enhancement (arrows) replacing the area of the cribriform plate in the anterior cranial skull base and extending into the nasal region. Severe sinus disease is seen. (d) Axial T2-weighted fat saturation (2,200/80) MR image shows that the mass (M) erodes the medial wall of the right maxillary sinus and left maxillary sinus with marked high signal intensity similar to that of mucosal thickening and fluid in both sinuses. Matrix mineralization cannot be seen. (e) Photograph of the gross specimen show portions of the cribriform plate superiorly, maxillary sinus, and lobules of cartilage growth (*).
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Figure 13d. Craniofacial conventional chondrosarcoma in a 26-year-old man with nasal symptoms. (a) Coronal CT reformatted image reveals a low-attenuation mass (M) replacing nasal bones and displacing the nasal septum with small subtle chondroid matrix mineralization (arrows). (b, c) Sagittal T1-weighted (570/15) MR image obtained without (b) and coronal T1-weighted MR image (570/15) obtained with (c) gadolinium show the low-signal-intensity mass (M) with mild peripheral and septal enhancement (arrows) replacing the area of the cribriform plate in the anterior cranial skull base and extending into the nasal region. Severe sinus disease is seen. (d) Axial T2-weighted fat saturation (2,200/80) MR image shows that the mass (M) erodes the medial wall of the right maxillary sinus and left maxillary sinus with marked high signal intensity similar to that of mucosal thickening and fluid in both sinuses. Matrix mineralization cannot be seen. (e) Photograph of the gross specimen show portions of the cribriform plate superiorly, maxillary sinus, and lobules of cartilage growth (*).
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Figure 13e. Craniofacial conventional chondrosarcoma in a 26-year-old man with nasal symptoms. (a) Coronal CT reformatted image reveals a low-attenuation mass (M) replacing nasal bones and displacing the nasal septum with small subtle chondroid matrix mineralization (arrows). (b, c) Sagittal T1-weighted (570/15) MR image obtained without (b) and coronal T1-weighted MR image (570/15) obtained with (c) gadolinium show the low-signal-intensity mass (M) with mild peripheral and septal enhancement (arrows) replacing the area of the cribriform plate in the anterior cranial skull base and extending into the nasal region. Severe sinus disease is seen. (d) Axial T2-weighted fat saturation (2,200/80) MR image shows that the mass (M) erodes the medial wall of the right maxillary sinus and left maxillary sinus with marked high signal intensity similar to that of mucosal thickening and fluid in both sinuses. Matrix mineralization cannot be seen. (e) Photograph of the gross specimen show portions of the cribriform plate superiorly, maxillary sinus, and lobules of cartilage growth (*).
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Radiographs of conventional chondrosarcoma typically reveal a mixed lytic and sclerotic appearance (Figs 9–12). The sclerotic areas represent chondroid matrix mineralization and are seen in 60%–78% of lesions (Figs 9–12) (1–5,13). The characteristic appearance of mineralized chondroid matrix is a ring-and-arc pattern of calcification (13,22–31). This pattern may coalesce to form a more radiopaque flocculent pattern of calcification. This characteristic chondroid calcification usually allows confident radiologic diagnosis of a cartilaginous lesion and is often the most dominant feature. This radiographic appearance represents the pathologic characteristic of enchondral ossification about the margins of the cartilaginous lobules. Higher-grade chondrosarcomas often contain relatively less extensive areas of matrix mineralization. The radiolucent component usually reveals geographic bone lysis and is multilobulated, directly corresponding to the growth pattern of this hyaline cartilage lesion (Figs 9, 10). More aggressive patterns of bone lysis (moth-eaten and permeative) may be seen with higher-grade conventional chondrosarcomas (grade 3), but they are much more frequently associated with mesenchymal, myxoid, and dedifferentiated cell types. Continued growth leads to lobulated endosteal scalloping that eventually produces cortical penetration (57% of long bone lesions on radiographs) and a soft-tissue component (46% of long bone lesions on radiographs) (Figs 9–11) (13). In our experience, the depth of endosteal scalloping at its most prominent focus is the best distinguishing feature between long bone enchondroma and chondrosarcoma (13,22). Endosteal scalloping greater than two-thirds the normal thickness of the long bone cortex is strong evidence of chondrosarcoma (75% of cases on radiographs) versus enchondroma (9% of cases on radiographs) (Figs 9, 10) (13). Extensive, longitudinal, endosteal scalloping in long bone lesions (along greater than two-thirds of lesion length) is also more suggestive of conventional chondrosarcoma than enchondroma, although it is not as distinctive a feature as the depth of scalloping.
Endosteal scalloping reflects lobular lesion growth and an attempt by the intramedullary malignancy to extend to a second compartment. However, because of the relatively slow growth of the lesion, the cortex responds to maintain the tumor in the medullary canal. This attempt to maintain a margin about the chondrosarcoma frequently leads to cortical remodeling, cortical thickening, and periosteal reaction, all of which are uncommonly associated with enchondroma. These findings are most likely to be seen in long bone lesions.
Bone scintigraphy usually reflects the increased physiologic activity of conventional intramedullary chondrosarcoma (13,21,32,33). The majority (82%) of long bone chondrosarcomas reveal marked increased radionuclide uptake compared with that in the anterior iliac crest, in contrast to long bone enchondromas, which show increased radiotracer activity in only 21% of cases (Figs 9, 10) (13). In addition, a heterogeneous pattern of radionuclide uptake is also more common in conventional intramedullary chondrosarcoma (63% of long bone chondrosarcomas versus 30% of enchondromas) (13). Technetium-99m–labeled dimercapto succinic acid (DMSA) radionuclide activity was seen in all cases of chondrosarcoma in a series of cases reported by Kobayashi and colleagues (33). In the future, positron emission tomography may be employed to help distinguish chondrosarcoma from enchondroma (34–36).
CT allows optimal detection and characterization of matrix mineralization, particularly when it is subtle or the lesion is in a complex area of anatomy. Areas of matrix mineralization are demonstrated by CT in 94% of long bone chondrosarcomas (Figs 9–12) (13). Neither the extent nor the presence of matrix mineralization identified on CT scans helps distinguish between long bone enchondroma and chondrosarcoma. The high sensitivity of CT for depiction of matrix mineralization (as compared with radiography) typically shows the matrix mineralization to be throughout the lesion.
Evaluation of endosteal scalloping depth is also aided by the three-dimensional imaging provided by CT compared with two-dimensional radiography (13,22–31,37–40). Long bone chondrosarcomas have focal areas of greater than two-thirds scalloping of the normal cortical thickness in 90% of cases, as opposed to enchondromas, which demonstrate this finding in only 10% of cases on CT scans (Figs 9, 10) (13). The longitudinal extent of endosteal scalloping on CT scans is usually throughout the lesion length in long bone chondrosarcomas (79%), as opposed to a shorter extent with enchondromas (13,21). Lobulated endosteal scalloping causing cortical destruction is common in long bone conventional chondrosarcomas on CT scans (88% of long bone lesions) but rare in enchondroma (8%) (13). Cortical response, including cortical thickening and periosteal reaction, to the chondrosarcoma in an attempt to confine the process to the medullary canal is equally well
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Abstract
LEARNING OBJECTIVES FOR TEST...
