DOI: 10.1148/rg.236025172
(Radiographics. 2003;23:1389-1399.)
© RSNA, 2003
Musculoskeletal Sarcoidosis: Spectrum of Appearances at MR Imaging1
Sandra L. Moore, MD and
Alvin E. Teirstein, MD
1 From the Department of Radiology, New York University School of Medicine, Tisch Hospital, 560 First Ave, New York, NY 10016 (S.M.); and the Department of Medicine, Pulmonary and Critical Care Division, Mount Sinai Medical School, New York, NY (A.E.T.). Presented as an education exhibit at the 2000 RSNA scientific assembly. Received November 21, 2002; revision requested January 2, 2003; revision received February 12; accepted February 21. Address correspondence to S.M. (e-mail: sandra.moore@med.nyu.edu).
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Abstract
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Magnetic resonance (MR) imaging reveals a broad range of musculoskeletal abnormalities in patients with sarcoidosis, including focal and diffuse muscle lesions, soft-tissue masses, joint abnormalities, and marrow infiltration of small and large bones. Long bone and axial skeletal involvement may be occult at conventional radiography but depicted at MR imaging, with an appearance that resembles that of osseous metastases. Sarcoidosis-related findings may be detected at dedicated MR imaging for osteoarticular symptoms in sarcoidosis patients or encountered incidentally at MR imaging performed for other indications. Correlation with clinical and laboratory findings is essential for correct diagnosis because the MR imaging findings are nonspecific in most cases. The radiologist should be aware of potential sarcoidal causes in the differential diagnosis of musculoskeletal lesions in patients with proved or suspected sarcoidosis. Such consideration will have a profound effect on the interpretation of images and on the study of patients with dual diagnoses of sarcoidosis and neoplasm.
© RSNA, 2003
Index Terms: Bones, diseases, **.222 • Bones, MR, **.1214 • Muscles, diseases, **.22 • Muscles, MR, **.1214 • Sarcoidosis, **.22
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LEARNING OBJECTIVES
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After reading this article and taking the test, the reader will be able to:
- Identify potential sarcoidal musculoskeletal lesions seen at MR imaging that are occult at conventional radiography.
- Describe the appearances and differential diagnoses of musculoskeletal lesions seen at MR imaging in patients with proved or suspected sarcoidosis.
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Introduction
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Sarcoidosis is an inflammatory disorder of unknown cause that is characterized by the presence of noncaseating granulomas in tissues, with no evidence of other known causes of granulomatous disease. Sarcoidosis involves multiple organs, most commonly the lungs, lymph nodes, skin, and eyes, but may be clinically evident in any organ system, including the musculoskeletal system. Skeletal involvement has been reported in 1%–13% of sarcoidosis patients, with an estimated average of 5% (1), a figure that is determined on the basis of findings at conventional radiography performed for the detection of bone disease. Although sarcoidosis patients commonly complain of bone and joint pain, imaging evaluation is often limited to radiography of the hands or feet that demonstrates either normal findings or lacelike osteolysis. Osteosclerotic manifestations are also seen, but infrequently. Involvement of the large bones and axial skeleton is considered uncommon and may not be evaluated with imaging.
Because of the excellent tissue contrast of magnetic resonance (MR) imaging, musculoskeletal abnormalities that are occult on radiographs may be seen on MR images obtained in sarcoidosis patients. These abnormalities include small and large bone marrow infiltration, focal and diffuse muscle lesions, soft-tissue infiltration, and masses. Other nonspecific associated findings seen at MR imaging include tendinopathy and tenosynovitis. Radiologists should be cognizant of the appearances, differential diagnoses, and extent of musculoskeletal lesions that may be seen at MR imaging in this patient population.
In this article, we present the spectrum of abnormalities found in patients from our Sarcoidosis Service who were referred for MR imaging evaluation of musculoskeletal symptoms. These abnormalities included osseous lesions (small and large bone sarcoidosis), sarcoidal arthropathy, and sarcoidal myopathy. All MR images were obtained with a 1.5-T imager (Signa Horizon or LX; GE Medical Systems, Milwaukee, Wis).
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Osseous Lesions
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Small Bone Sarcoidosis
Classic sarcoidal lesions in the small bones of the hands and feet are well characterized and diagnosed with conventional radiographs, on which they demonstrate the familiar "lacy" lytic appearance (Fig 1). The resulting alignment deformities in the hands and feet are often due to pathologic fractures with bone collapse rather than joint abnormalities.
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Figure 1. Small bone sarcoidosis. Close-up view from a posteroanterior radiograph of the finger shows sarcoidosis with the classic lacy lytic pattern involving the middle phalanx. The articular surface is spared.
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MR imaging of sarcoidal lesions of the small bones provides information not available at radiography, demonstrating marrow lesions that are radiographically occult, extension of granulomas beyond the cortex (Fig 2a, 2b), and periosseous soft-tissue involvement. Although the absence of periostitis in sarcoidal bone lesions has been noted at conventional radiography (2), MR imaging may demonstrate fine perpendicular lines extending from the ghost of the cortex and resembling periostitis (Fig 2c, 2d). MR imaging is not necessary for the diagnosis of sarcoidal lesions of the small bones of the hands and feet but may be helpful in developing the differential diagnosis. For example, in the evaluation of dactylitis in a patient with both gout and sarcoidosis, intermediate-density–weighted MR imaging can help differentiate tophus (usually remains hypointense) (Fig 3) from sarcoidal nodules (typically hyperintense) (3,4).
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Figure 2a. Small bone sarcoidosis in a 53-year-old woman with a 12-year history of painful swelling of the digits. (a) Axial T2-weighted MR image (repetition time msec/echo time msec = 4,000/85) demonstrates swelling of the fifth finger with destruction of the cortex of the proximal phalanx. Periosseous extension of presumed sarcoidosis nodules with intermediate signal intensity is also seen (arrow). (b) Axial fat-saturated proton-density-weighted MR image (1,200/20) of the digits reveals a conglomerate nodular mass with bright signal intensity infiltrating the fifth proximal phalanx and destroying the cortex. (c) Coronal T1-weighted MR image (500/20) demonstrates a low-signal-intensity intramedullary mass of the fifth digit with fine perpendicular lines extending from the ghost of the cortex. Although this finding resembles periosteal reaction, it may represent periosseous extension of granulomas separated by fibroblasts and collagen. (d) Coronal fat-saturated proton-density-weighted MR image (2,000/22) also demonstrates fine perpendicular lines extending from the intramedullary lesion.
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Figure 2b. Small bone sarcoidosis in a 53-year-old woman with a 12-year history of painful swelling of the digits. (a) Axial T2-weighted MR image (repetition time msec/echo time msec = 4,000/85) demonstrates swelling of the fifth finger with destruction of the cortex of the proximal phalanx. Periosseous extension of presumed sarcoidosis nodules with intermediate signal intensity is also seen (arrow). (b) Axial fat-saturated proton-density-weighted MR image (1,200/20) of the digits reveals a conglomerate nodular mass with bright signal intensity infiltrating the fifth proximal phalanx and destroying the cortex. (c) Coronal T1-weighted MR image (500/20) demonstrates a low-signal-intensity intramedullary mass of the fifth digit with fine perpendicular lines extending from the ghost of the cortex. Although this finding resembles periosteal reaction, it may represent periosseous extension of granulomas separated by fibroblasts and collagen. (d) Coronal fat-saturated proton-density-weighted MR image (2,000/22) also demonstrates fine perpendicular lines extending from the intramedullary lesion.
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Figure 2c. Small bone sarcoidosis in a 53-year-old woman with a 12-year history of painful swelling of the digits. (a) Axial T2-weighted MR image (repetition time msec/echo time msec = 4,000/85) demonstrates swelling of the fifth finger with destruction of the cortex of the proximal phalanx. Periosseous extension of presumed sarcoidosis nodules with intermediate signal intensity is also seen (arrow). (b) Axial fat-saturated proton-density-weighted MR image (1,200/20) of the digits reveals a conglomerate nodular mass with bright signal intensity infiltrating the fifth proximal phalanx and destroying the cortex. (c) Coronal T1-weighted MR image (500/20) demonstrates a low-signal-intensity intramedullary mass of the fifth digit with fine perpendicular lines extending from the ghost of the cortex. Although this finding resembles periosteal reaction, it may represent periosseous extension of granulomas separated by fibroblasts and collagen. (d) Coronal fat-saturated proton-density-weighted MR image (2,000/22) also demonstrates fine perpendicular lines extending from the intramedullary lesion.
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Figure 2d. Small bone sarcoidosis in a 53-year-old woman with a 12-year history of painful swelling of the digits. (a) Axial T2-weighted MR image (repetition time msec/echo time msec = 4,000/85) demonstrates swelling of the fifth finger with destruction of the cortex of the proximal phalanx. Periosseous extension of presumed sarcoidosis nodules with intermediate signal intensity is also seen (arrow). (b) Axial fat-saturated proton-density-weighted MR image (1,200/20) of the digits reveals a conglomerate nodular mass with bright signal intensity infiltrating the fifth proximal phalanx and destroying the cortex. (c) Coronal T1-weighted MR image (500/20) demonstrates a low-signal-intensity intramedullary mass of the fifth digit with fine perpendicular lines extending from the ghost of the cortex. Although this finding resembles periosteal reaction, it may represent periosseous extension of granulomas separated by fibroblasts and collagen. (d) Coronal fat-saturated proton-density-weighted MR image (2,000/22) also demonstrates fine perpendicular lines extending from the intramedullary lesion.
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Figure 3a. Dactylitis in a 39-year-old man with sarcoidosis and hyperuricemia. (a) Posteroanterior radiograph of the hand shows eccentric swelling about the fifth digit. A faint erosion or cyst is seen at the medial margin of the proximal middle phalanx, along with cortical erosion in the distal phalanx. Gout was the favored radiologic diagnosis, but needle aspiration biopsy was not diagnostic. (b) Axial proton-density-weighted MR image (2,600/15) demonstrates low-signal-intensity material in the soft tissues about the second and fifth digits and extending into the medullary cavity of the fifth middle phalanx. (c-e) On axial fat-saturated T2-weighted (3,000/90) (c), coronal T1-weighted (450/10) (d), and coronal fat-saturated intermediate-density-weighted (1,600/16) (e) MR images, the paraosseous material remains low in signal intensity (arrows in d and e). A cystlike lesion whose contents demonstrate increased signal intensity is noted at the base of the fifth middle phalanx (arrowhead in e).
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Figure 3b. Dactylitis in a 39-year-old man with sarcoidosis and hyperuricemia. (a) Posteroanterior radiograph of the hand shows eccentric swelling about the fifth digit. A faint erosion or cyst is seen at the medial margin of the proximal middle phalanx, along with cortical erosion in the distal phalanx. Gout was the favored radiologic diagnosis, but needle aspiration biopsy was not diagnostic. (b) Axial proton-density-weighted MR image (2,600/15) demonstrates low-signal-intensity material in the soft tissues about the second and fifth digits and extending into the medullary cavity of the fifth middle phalanx. (c-e) On axial fat-saturated T2-weighted (3,000/90) (c), coronal T1-weighted (450/10) (d), and coronal fat-saturated intermediate-density-weighted (1,600/16) (e) MR images, the paraosseous material remains low in signal intensity (arrows in d and e). A cystlike lesion whose contents demonstrate increased signal intensity is noted at the base of the fifth middle phalanx (arrowhead in e).
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Figure 3c. Dactylitis in a 39-year-old man with sarcoidosis and hyperuricemia. (a) Posteroanterior radiograph of the hand shows eccentric swelling about the fifth digit. A faint erosion or cyst is seen at the medial margin of the proximal middle phalanx, along with cortical erosion in the distal phalanx. Gout was the favored radiologic diagnosis, but needle aspiration biopsy was not diagnostic. (b) Axial proton-density-weighted MR image (2,600/15) demonstrates low-signal-intensity material in the soft tissues about the second and fifth digits and extending into the medullary cavity of the fifth middle phalanx. (c-e) On axial fat-saturated T2-weighted (3,000/90) (c), coronal T1-weighted (450/10) (d), and coronal fat-saturated intermediate-density-weighted (1,600/16) (e) MR images, the paraosseous material remains low in signal intensity (arrows in d and e). A cystlike lesion whose contents demonstrate increased signal intensity is noted at the base of the fifth middle phalanx (arrowhead in e).
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Figure 3d. Dactylitis in a 39-year-old man with sarcoidosis and hyperuricemia. (a) Posteroanterior radiograph of the hand shows eccentric swelling about the fifth digit. A faint erosion or cyst is seen at the medial margin of the proximal middle phalanx, along with cortical erosion in the distal phalanx. Gout was the favored radiologic diagnosis, but needle aspiration biopsy was not diagnostic. (b) Axial proton-density-weighted MR image (2,600/15) demonstrates low-signal-intensity material in the soft tissues about the second and fifth digits and extending into the medullary cavity of the fifth middle phalanx. (c-e) On axial fat-saturated T2-weighted (3,000/90) (c), coronal T1-weighted (450/10) (d), and coronal fat-saturated intermediate-density-weighted (1,600/16) (e) MR images, the paraosseous material remains low in signal intensity (arrows in d and e). A cystlike lesion whose contents demonstrate increased signal intensity is noted at the base of the fifth middle phalanx (arrowhead in e).
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Figure 3e. Dactylitis in a 39-year-old man with sarcoidosis and hyperuricemia. (a) Posteroanterior radiograph of the hand shows eccentric swelling about the fifth digit. A faint erosion or cyst is seen at the medial margin of the proximal middle phalanx, along with cortical erosion in the distal phalanx. Gout was the favored radiologic diagnosis, but needle aspiration biopsy was not diagnostic. (b) Axial proton-density-weighted MR image (2,600/15) demonstrates low-signal-intensity material in the soft tissues about the second and fifth digits and extending into the medullary cavity of the fifth middle phalanx. (c-e) On axial fat-saturated T2-weighted (3,000/90) (c), coronal T1-weighted (450/10) (d), and coronal fat-saturated intermediate-density-weighted (1,600/16) (e) MR images, the paraosseous material remains low in signal intensity (arrows in d and e). A cystlike lesion whose contents demonstrate increased signal intensity is noted at the base of the fifth middle phalanx (arrowhead in e).
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Clinicians do not usually request biopsy of digital lesions with radiographic appearance considered pathognomonic in the setting of known sarcoidosis. Differentiation from tuberous sclerosis and enchondromatosis can usually be made clinically.
Large Bone Sarcoidosis
Sarcoidal lesions detected at radiography of the axial skeleton and long bones are considered uncommon (5). Large bone lesions may be painful or asymptomatic. Neither bone scintigraphy nor skeletal survey has proved reliable in screening for sarcoidal bone lesions (6). We determine the MR imaging site on the basis of symptoms.
Sarcoidal large bone lesions may manifest radiographically as focal lysis or sclerosis or may be occult (Figs 4a, 5b). MR imaging reveals indistinct or well-marginated lesions of varying sizes. In the 13 sarcoidosis patients in our study with large bone lesions at MR imaging, the lesions had a variety of appearances, including round, cannonball-like intramedullary lesions (Figs 4b, 4c, 5a), confluent irregular marrow infiltration (Fig 6), less well defined discrete lesions with a "starry sky" appearance (Fig 7), and patchy, diffuse intramedullary lesions. The lesions we observed had decreased signal intensity on T1-weighted MR images. The signal intensity of the lesions is variable; occasionally, the lesions have low signal intensity, but in most cases they have increased signal intensity on inversion-recovery, T2-weighted, and fat-saturated proton-density–weighted MR images. The lesions may enhance after intravenous administration of gadopentetate dimeglumine, although contrast material does not usually increase the conspicuity of these lesions relative to their appearance on fat-saturated proton-density–weighted images. MR imaging evidence of cortical destruction, often seen in the small bone lesions, was not a common feature of the large bone lesions. Some of the intramedullary lesions contain focal areas with signal intensity characteristics corresponding to fat (Fig 5c) or form a convex margin with marrow fat (Fig 4d), findings that in some cases may be useful in differentiating these lesions from osseous metastases. The appearance and signal intensity characteristics of these lesions are otherwise nonspecific. The principal differential considerations include osseous metastases, lymphoma, myeloma, rarely disseminated infection such as tuberculosis, or serous atrophy (a gelatinous transformation of the marrow that is uncommonly detected in patients with acquired immunodeficiency syndrome, anorexia nervosa, or malignancies). In some cases, the sarcoidal lesions have resolved on follow-up studies, with ghosts of the prior lesions having a signal intensity that indicates the presence of fat or fibrosis (Fig 4e, 4f) (5). The dynamics of the disease process and the activity of the lesions (ie, stable, progressing, or resolving) are probably critical factors that affect signal intensity and morphology; however, further study is needed to understand the natural history of these lesions at MR imaging.
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Figure 4a. Large bone sarcoidosis in a 48-year-old man with left hip pain. (a) Anteroposterior radiograph shows the normal pelvis. (b, c) Coronal T1-weighted (450/8) (b) and fat-saturated intermediate-density-weighted (2,000/15) (c) MR images demonstrate numerous discrete round lesions within the lumbar vertebrae, the pelvis, and both proximal femurs. As seen here, these lesions typically have low signal intensity on T1-weighted images and bright signal intensity on fat-saturated proton-density-weighted images. (d) Close-up view from a coronal fat-saturated intermediate-density-weighted MR image (2,000/15) reveals lesions that have increased signal intensity and form a convex border with the adjacent marrow fat (arrow). (e, f) Coronal T1-weighted (500/8) (e) and fat-saturated intermediate-density-weighted (2,000/15) (f) MR images obtained 7 months later show nearly complete resolution of the previously detected intramedullary lesions. Faint low-signal-intensity ghosts of the lesions persist (arrow in f). The patient did not undergo treatment for sarcoidosis.
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Figure 4b. Large bone sarcoidosis in a 48-year-old man with left hip pain. (a) Anteroposterior radiograph shows the normal pelvis. (b, c) Coronal T1-weighted (450/8) (b) and fat-saturated intermediate-density-weighted (2,000/15) (c) MR images demonstrate numerous discrete round lesions within the lumbar vertebrae, the pelvis, and both proximal femurs. As seen here, these lesions typically have low signal intensity on T1-weighted images and bright signal intensity on fat-saturated proton-density-weighted images. (d) Close-up view from a coronal fat-saturated intermediate-density-weighted MR image (2,000/15) reveals lesions that have increased signal intensity and form a convex border with the adjacent marrow fat (arrow). (e, f) Coronal T1-weighted (500/8) (e) and fat-saturated intermediate-density-weighted (2,000/15) (f) MR images obtained 7 months later show nearly complete resolution of the previously detected intramedullary lesions. Faint low-signal-intensity ghosts of the lesions persist (arrow in f). The patient did not undergo treatment for sarcoidosis.
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Figure 4c. Large bone sarcoidosis in a 48-year-old man with left hip pain. (a) Anteroposterior radiograph shows the normal pelvis. (b, c) Coronal T1-weighted (450/8) (b) and fat-saturated intermediate-density-weighted (2,000/15) (c) MR images demonstrate numerous discrete round lesions within the lumbar vertebrae, the pelvis, and both proximal femurs. As seen here, these lesions typically have low signal intensity on T1-weighted images and bright signal intensity on fat-saturated proton-density-weighted images. (d) Close-up view from a coronal fat-saturated intermediate-density-weighted MR image (2,000/15) reveals lesions that have increased signal intensity and form a convex border with the adjacent marrow fat (arrow). (e, f) Coronal T1-weighted (500/8) (e) and fat-saturated intermediate-density-weighted (2,000/15) (f) MR images obtained 7 months later show nearly complete resolution of the previously detected intramedullary lesions. Faint low-signal-intensity ghosts of the lesions persist (arrow in f). The patient did not undergo treatment for sarcoidosis.
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Figure 4d. Large bone sarcoidosis in a 48-year-old man with left hip pain. (a) Anteroposterior radiograph shows the normal pelvis. (b, c) Coronal T1-weighted (450/8) (b) and fat-saturated intermediate-density-weighted (2,000/15) (c) MR images demonstrate numerous discrete round lesions within the lumbar vertebrae, the pelvis, and both proximal femurs. As seen here, these lesions typically have low signal intensity on T1-weighted images and bright signal intensity on fat-saturated proton-density-weighted images. (d) Close-up view from a coronal fat-saturated intermediate-density-weighted MR image (2,000/15) reveals lesions that have increased signal intensity and form a convex border with the adjacent marrow fat (arrow). (e, f) Coronal T1-weighted (500/8) (e) and fat-saturated intermediate-density-weighted (2,000/15) (f) MR images obtained 7 months later show nearly complete resolution of the previously detected intramedullary lesions. Faint low-signal-intensity ghosts of the lesions persist (arrow in f). The patient did not undergo treatment for sarcoidosis.
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Figure 4e. Large bone sarcoidosis in a 48-year-old man with left hip pain. (a) Anteroposterior radiograph shows the normal pelvis. (b, c) Coronal T1-weighted (450/8) (b) and fat-saturated intermediate-density-weighted (2,000/15) (c) MR images demonstrate numerous discrete round lesions within the lumbar vertebrae, the pelvis, and both proximal femurs. As seen here, these lesions typically have low signal intensity on T1-weighted images and bright signal intensity on fat-saturated proton-density-weighted images. (d) Close-up view from a coronal fat-saturated intermediate-density-weighted MR image (2,000/15) reveals lesions that have increased signal intensity and form a convex border with the adjacent marrow fat (arrow). (e, f) Coronal T1-weighted (500/8) (e) and fat-saturated intermediate-density-weighted (2,000/15) (f) MR images obtained 7 months later show nearly complete resolution of the previously detected intramedullary lesions. Faint low-signal-intensity ghosts of the lesions persist (arrow in f). The patient did not undergo treatment for sarcoidosis.
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Figure 4f. Large bone sarcoidosis in a 48-year-old man with left hip pain. (a) Anteroposterior radiograph shows the normal pelvis. (b, c) Coronal T1-weighted (450/8) (b) and fat-saturated intermediate-density-weighted (2,000/15) (c) MR images demonstrate numerous discrete round lesions within the lumbar vertebrae, the pelvis, and both proximal femurs. As seen here, these lesions typically have low signal intensity on T1-weighted images and bright signal intensity on fat-saturated proton-density-weighted images. (d) Close-up view from a coronal fat-saturated intermediate-density-weighted MR image (2,000/15) reveals lesions that have increased signal intensity and form a convex border with the adjacent marrow fat (arrow). (e, f) Coronal T1-weighted (500/8) (e) and fat-saturated intermediate-density-weighted (2,000/15) (f) MR images obtained 7 months later show nearly complete resolution of the previously detected intramedullary lesions. Faint low-signal-intensity ghosts of the lesions persist (arrow in f). The patient did not undergo treatment for sarcoidosis.
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Figure 5a. Large bone sarcoidosis in a 53-year-old woman with bilateral heel pain. The patient’s medical history was unknown. (a) Sagittal T1-weighted MR image (450/10) demonstrates a round, low-signal-intensity lesion that involves the plantar aspect of the calcaneus. Biopsy of a lesion of the contralateral calcaneus (not shown) revealed noncaseating granulomas and led to further clinical evaluation, results of which confirmed systemic sarcoidosis. (b) Lateral radiograph of the ankle reveals a faint area of increased opacity in the area of the lesion seen at MR imaging, with no radiographic evidence of trabecular or cortical disruption. The radiograph was interpreted as normal. (c) Sagittal fat-saturated T1-weighted MR image (650/8) obtained after the intravenous administration of gadopentetate dimeglumine shows an indistinctly marginated area of enhancement with a central area of spared marrow in the contralateral calcaneus (arrow).
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Figure 5b. Large bone sarcoidosis in a 53-year-old woman with bilateral heel pain. The patient’s medical history was unknown. (a) Sagittal T1-weighted MR image (450/10) demonstrates a round, low-signal-intensity lesion that involves the plantar aspect of the calcaneus. Biopsy of a lesion of the contralateral calcaneus (not shown) revealed noncaseating granulomas and led to further clinical evaluation, results of which confirmed systemic sarcoidosis. (b) Lateral radiograph of the ankle reveals a faint area of increased opacity in the area of the lesion seen at MR imaging, with no radiographic evidence of trabecular or cortical disruption. The radiograph was interpreted as normal. (c) Sagittal fat-saturated T1-weighted MR image (650/8) obtained after the intravenous administration of gadopentetate dimeglumine shows an indistinctly marginated area of enhancement with a central area of spared marrow in the contralateral calcaneus (arrow).
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Figure 5c. Large bone sarcoidosis in a 53-year-old woman with bilateral heel pain. The patient’s medical history was unknown. (a) Sagittal T1-weighted MR image (450/10) demonstrates a round, low-signal-intensity lesion that involves the plantar aspect of the calcaneus. Biopsy of a lesion of the contralateral calcaneus (not shown) revealed noncaseating granulomas and led to further clinical evaluation, results of which confirmed systemic sarcoidosis. (b) Lateral radiograph of the ankle reveals a faint area of increased opacity in the area of the lesion seen at MR imaging, with no radiographic evidence of trabecular or cortical disruption. The radiograph was interpreted as normal. (c) Sagittal fat-saturated T1-weighted MR image (650/8) obtained after the intravenous administration of gadopentetate dimeglumine shows an indistinctly marginated area of enhancement with a central area of spared marrow in the contralateral calcaneus (arrow).
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Figure 6. Large bone sarcoidosis in a 54-year-old woman. Coronal T1-weighted MR image (450/14) shows an irregular area of decreased signal intensity in the left iliac bone (arrows). The increased signal intensity centrally within the lesion represents fat. Biopsy of the lesion revealed noncaseating granulomas.
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Figure 7. Large bone sarcoidosis in a 41-year-old man. Coronal fat-saturated intermediate-density-weighted MR image (3,899/28) shows a diffuse stippled pattern of abnormal signal intensity throughout the marrow of the pelvic bones. Biopsy was positive for noncaseating granulomas.
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Calvarial sarcoidosis may manifest as expansile lesions, which can be evaluated with computed tomography (CT); MR imaging can be used to further assess the associated soft tissues when needed (Fig 8). Differential considerations include hemangioma, eosinophilic granuloma, metastases, and other tumors as well as chronic infection (5,7).
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Figure 8a. Calvarial lesion in a 34-year-old woman with sarcoidosis. Bone scintigraphy showed radiotracer uptake in the left temporal bone. (a) Axial CT scan shows a subtle expansile lesion of the left temporal bone with cortical thinning (arrow). (b) Axial T1-weighted MR image (450/8) shows low-signal-intensity intramedullary infiltrate in the left temporal bone (arrow). The lesion is more conspicuous at CT. No extraosseous mass was demonstrated. The patient declined to undergo biopsy.
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Figure 8b. Calvarial lesion in a 34-year-old woman with sarcoidosis. Bone scintigraphy showed radiotracer uptake in the left temporal bone. (a) Axial CT scan shows a subtle expansile lesion of the left temporal bone with cortical thinning (arrow). (b) Axial T1-weighted MR image (450/8) shows low-signal-intensity intramedullary infiltrate in the left temporal bone (arrow). The lesion is more conspicuous at CT. No extraosseous mass was demonstrated. The patient declined to undergo biopsy.
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Sarcoidosis patients may have other bone diseases that complicate the assessment of granulomatous infiltration of the marrow, including elevated vitamin D levels secondary to the elaboration of vitamin D precursors by the granulomas (8,9), secondary hyperparathyroidism due to renal failure, and osteopenia with or without corticosteroid treatment. Corticosteroid treatment for sarcoidosis can result in avascular necrosis, osteoporosis, and fractures. Correlation of the MR imaging findings with radiographic findings, laboratory data, clinical manifestations, and treatment is necessary to understand and differentiate the findings.
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Sarcoidal Arthropathy
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Löfgren syndrome is a well-recognized manifestation of sarcoidosis, with patients exhibiting arthralgias, erythema nodosum, and bilateral hilar lymph node enlargement. The arthralgia is thought to be due to the effect of circulating inflammatory cytokines on the joints rather than granulomatous disease per se (10,11). The early pattern, usually seen in the first 6 months of symptoms, consists of polyarticular involvement of the ankles, knees, proximal interphalangeal joints, wrists, and elbows. Monoarthritis is unusual, as is effusion. Pain and stiffness are often worse than objective signs suggest. Conventional radiographs of the symptomatic joints are usually negative or show only osteoporosis and soft-tissue swelling. The principal radiographic differential diagnosis is rheumatoid arthritis; however, the clinical setting rather than the radiographic appearance provokes consideration of the diagnosis of sarcoidosis.
In addition to Löfgren syndrome, significant joint symptoms are encountered in 10%–35% of sarcoidosis patients, more commonly in women, due to granulomatous arthritis (5). These patients usually have granulomatous synovitis, with a chronic transient or relapsing sarcoidal arthropathy. This second form of sarcoidal arthritis, observed 6 months or more after the diagnosis of sarcoidosis, usually involves two or three joints, including the knees, ankles, proximal interphalangeal joints, and occasionally the wrists or shoulders. Sausage-like dactylitis of the fingers can occur. This arthritis is commonly associated with cutaneous sarcoidosis, but not with erythema nodosum (5), and may subside or recur. Pain is usually not intense. Radiographic changes consist of cysts in the phalanges.
Acute or chronic sarcoidal arthropathy is usually detected with clinical criteria, including negative serologic findings for rheumatoid factor and antinuclear antibodies, and patients may not be referred for MR imaging. However, MR imaging of the joints may depict lesions that are occult at conventional radiography. Tenosynovitis, tendonitis, bursitis, and synovitis can be demonstrated at MR imaging but are nonspecific findings and may require synovial or soft-tissue biopsy to establish the granulomatous cause (Figs 9, 10).
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Figure 9. Sarcoidal arthropathy in a 52-year-old woman. On an axial contrast-enhanced fat-saturated T1-weighted MR image (500/10) of the distal forearm, the extensor tendon sheath is distended with fluid and shows synovial enhancement. Synovial biopsy revealed noncaseating granulomas.
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Figure 10. Presumed sarcoidal arthropathy in a 34-year-old woman with extensive bone involvement of the hands and feet. Axial intermediate-density-weighted MR image (4,016/15) of the left ankle demonstrates tenosynovitis of the peroneal tendon sheath (left arrow) and tendonosis of the Achilles tendon (right arrow). A subtle focus of abnormal marrow signal intensity is noted in the distal fibula.
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Sarcoidal Myopathy
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Discrete sarcoidal muscle lesions are reported in 1.4% of known sarcoidosis cases (12). However, biopsy demonstrates skeletal muscle granulomas in 50%–80% of sarcoidosis patients (5), most often in the absence of signs and symptoms. Nodular sarcoidal myopathy manifests at MR imaging as focal intramuscular masses, often at the musculotendinous junction. The nodules may be tender but usually manifest as soft-tissue masses. These masses may be multiple and bilateral and more commonly involve the lower extremity (12,13). The lesions are most conspicuous on T2-weighted MR images and on intravenous contrast material–enhanced images. The lesions have an umbilicated appearance, with a bright rim and low signal intensity centrally on T2-weighted and contrast-enhanced images. This finding has been described as having a "dark star" appearance (Fig 11) (13). On coronal and sagittal views, these lesions may have an elongated, cordlike appearance.
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Figure 11. Nodular sarcoidal myopathy in a 51-year-old woman with a 2-year history of sarcoidosis and painful nodules in both legs. Axial fat-saturated T1-weighted MR image (616/9) through the midcalf obtained after intravenous administration of gadopentetate dimeglumine shows multiple intramuscular lesions with thick rimlike enhancement and central low signal intensity (arrows). Biopsy revealed noncaseating granulomas.
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At clinical examination, generalized sarcoidal myopathy resembles polymyositis, with symmetric proximal weakness, elevated serum creatine kinase and aldolase levels, and myopathy at electromyographic evaluation. Discrete masses are not evident, but meticulous histologic examination of the tissue reveals noncaseating granulomas.
MR findings in sarcoidal myopathy are nonspecific and demonstrate proximal muscle atrophy with fatty replacement (Fig 12). Because corticosteroid therapy can be a confounding factor in the evaluation of potential sarcoidal muscle atrophy, differentiation from corticosteroid myopathy is based on clinical and other laboratory information. MR imaging is useful in demonstrating the extent of fatty replacement and determining optimal sites for muscle biopsy.
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Figure 12. Nonspecific myopathy in a woman with leg weakness who had undergone long-term corticosteroid treatment for presumed sarcoidal myopathy. Prior muscle biopsy had demonstrated noncaseating granulomas. Coronal T1-weighted MR image (716/12) of the thighs demonstrates extensive fatty replacement of the thigh muscles.
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Sarcoidal subcutaneous granulomatous infiltration, skin nodules, and soft-tissue masses associated with lymphadenopathy may be detected on MR images. The soft-tissue lesions may be discrete or indistinct and have nonspecific signal intensity characteristics that correspond to solid mesenchymal masses. These lesions demonstrate increased signal intensity on water-sensitive images, low signal intensity on T1-weighted images, and enhancement on contrast-enhanced images. Differential diagnosis includes other benign and malignant mesenchymal masses including tophus, pannus, and xanthoma. The optimized tissue contrast and multiplanar capability of MR imaging are useful in delineating the size, extent, morphology, and signal intensity and enhancement characteristics of these lesions and their relationship to surrounding structures. This information is useful in identifying a biopsy site (Figs 13, 14).
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Figure 13. Sarcoidal myopathy in a 38-year-old man with thigh swelling. Axial T1-weighted MR image (450/13) demonstrates focal subcutaneous reticulation with low signal intensity at the anterolateral aspect of the midthigh (arrow). A study performed 10 months earlier had yielded the same finding. Biopsy was positive for noncaseating granulomas.
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Figure 14. Sarcoidal mass in a patient with swelling over the left temporal area. Axial fat-saturated T1-weighted MR image (416/8) of the head shows a solid enhancing mass over the left calvaria and insinuating itself into the temporal muscle (arrow). Biopsy of an adjacent ocular mass (not shown) was positive for noncaseating granulomas.
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Conclusions
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MR imaging improves the detection of musculoskeletal disease in sarcoidosis patients, revealing disease not seen at conventional radiography. Correlation with clinical and laboratory findings is essential for correct diagnosis because the MR imaging findings are nonspecific in most cases. In a patient with biopsy-proved sarcoidosis, biopsy of the musculoskeletal lesion(s) detected at MR imaging may not be necessary. Nodular muscle lesions and some bone lesions with central fatty deposition have fairly specific MR imaging appearances, which may obviate biopsy. However, in some patients in whom sarcoidosis is not proved or a second comorbidity is suspected, biopsy of the musculoskeletal abnormality is indicated. Close cooperation with the clinician in making a decision regarding biopsy is recommended. Because sarcoidal lesions of the large bones resemble osseous metastases at MR imaging, the consideration of possible sarcoidal bone involvement has a profound effect on the interpretation of images and on the study of patients with dual diagnoses of sarcoidosis and neoplasm.
The detection of sarcoidal musculoskeletal lesions at MR imaging can change the clinical assessment of granulomatous load and the assessment of the severity of the disease and may influence treatment. Sarcoidosis should be considered in the differential diagnosis of musculoskeletal lesions detected at MR imaging in patients with suspected or proved sarcoidosis.
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Footnotes
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2** indicates multiple body systems. 
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References
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- James DG, Neville E, Carstairs LS. Bone and joint sarcoidosis. Semin Arthritis Rheum 1976; 6:53-81.[CrossRef][Medline]
- Beasley EW, III, Peterman SB, Hertzler GL. An unusual form of tibial sarcoidosis. AJR Am J Roentgenol 1987; 149:754-756.[Free Full Text]
- Popp JD, Bidgood WD, Edwards NL. Magnetic resonance imaging of tophaceous gout in the hands and wrists. Semin Arthritis Rheum 1996; 25:282-289.[CrossRef][Medline]
- Resnick D, Niwayama G. Gouty arthritis. In: Resnick D, Niwayama G, eds. Diagnosis of bone and joint disorders. 3rd ed. Philadelphia, Pa: Saunders, 1995; 1511-1555.
- Resnick D, Niwayama G. Sarcoidosis. In: Resnick D, Niwayama G, eds. Diagnosis of bone and joint disorders. 3rd ed. Philadelphia, Pa: Saunders, 1995; 4333-4352.
- Milman N, Lund JO, Graudal N, et al. Diagnostic value of routine radioisotope bone scanning in a series of 63 patients with pulmonary sarcoidosis. Sarcoidosis Vasc Diffuse Lung Dis 2000; 17:67-70.[Medline]
- Teirstein AS, Wolf BS, Siltzbach LE. Sarcoidosis of the skull. N Engl J Med 1961; 265:65-68.
- DeSimone DP, Brilliant HL, Basile J, et al. Granulomatous infiltration of the talus and abnormal vitamin D and calcium metabolism in a patient with sarcoidosis: successful treatment with hydroxychloroquine. Am J Med 1989; 87:694-696.[Medline]
- Fuss M, Pepersack T, Gillet C, et al. Calcium and vitamin D metabolism in granulomatous disease. Clin Rheumatol 1992; 11:28-36.[CrossRef][Medline]
- Visser H, Vos K, Zanelli E, et al. Sarcoid arthritis: clinical characteristics, diagnostic aspects, and risk factors. Ann Rheum Dis 2002; 61:499-504.[Abstract/Free Full Text]
- Murphy EP, McEvoy A, Conneely OM, Bresnihan B, FitzGerald O. Involvement of the nuclear orphan receptor NURR1 in the regulation of corticotropin-releasing hormone expression and actions in human inflammatory arthritis. Arthritis Rheum 2001; 44:782-793.[CrossRef][Medline]
- Otake S, Ishigaki T. Muscular sarcoidosis. Semin Musculoskelet Radiol 2001; 5:167-170.[CrossRef][Medline]
- Otake S. Sarcoidosis involving skeletal muscle: imaging findings and relative value of imaging procedures. AJR Am J Roentgenol 1994; 162:369- 375.[Abstract/Free Full Text]
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Abstract
LEARNING OBJECTIVES
