Radiography
Findings
Radiography is often the initial study obtained for the evaluation of synovial sarcoma. In 50% of patients with synovial sarcoma, radiographic findings are interpreted as normal (see Image 7). If an abnormality is present, the radiograph may reveal a well-defined, round or lobulated soft-tissue mass that averages approximately 8 cm in its largest dimension.
Approximately 30% of patients have calcifications that are detectable radiographically (see Images 1 and 4). The calcifications may be focal or spread throughout most of the tumor, and they may appear fine, stippled, or opaque.
Uncommonly, tumors can erode bone. Adjacent periosteal reaction can be seen in as many as 20% of patients. Distant metastases to bone are usually of the lytic and/or mixed variety.
When the neoplasm is near a joint and causes limitation of movement, periarticular osteoporosis may be seen.
Computed Tomography
Findings
CT scan findings are nonspecific and usually demonstrate a single round or lobulated mass with a soft-tissue density. The lesions measure approximately 3-12 cm in their largest dimension and are usually found near a joint. Masses in the head and neck or distal extremities are smaller at presentation, presumably secondary to an early mass effect.
The mass is usually well defined (see Images 6 and 8) but can occasionally appear infiltrative and can be homogeneous and show homogeneous enhancement, particularly in smaller lesions; alternatively, if hemorrhage or necrosis has occurred, the lesion may be multiloculated and show heterogeneous enhancement.8,9
Calcifications are demonstrated in 30% of patients;1 typically, diffuse punctate calcifications are revealed. These are often more concentrated at the periphery than at the center. Extensive calcifications can be similar in appearance to osteosarcoma or a calcified chondroid lesion. Densely calcified lesions, when found near a joint, may simulate tumoral calcinosis (see Image 5).
Involvement of the adjacent bone can cause changes, including cortical invasion with a wide zone of transition, bone remodeling from pressure erosion, and/or adjacent periosteal reaction.
Magnetic Resonance Imaging
Findings
Synovial sarcoma tumors tend to be large, averaging approximately 8 cm in their largest dimension, which is usually parallel to the long axis of the body. Approximately 91% of patients have a well-defined ovoid lesion with rounded or gently lobulated margins (see Image 9).9 The effect on adjacent structures is usually displacement, rather than invasion or destruction.
Most tumors display a heterogeneous intermediate signal intensity on T1-weighted MRIs. Lesions smaller than 5 cm are more likely to have a predominantly homogeneous signal intensity that is similar to that of the adjacent muscle (see Image 9). Larger lesions are most often heterogeneous secondary to extensive areas of hemorrhage and necrosis (see Image 11).
On T2-weighted images, lesions are usually hyperintense, with a signal intensity similar to or higher than that of fatty tissue (see Image 3). Considerable inhomogeneity is demonstrated in 82% of lesions, with cystic components seen in 77% (see Images 10 and 12).9 Cystic components with striking fluid-fluid levels are demonstrated in 18% of tumors.9 Approximately one third of lesions demonstrate the "triple signal pattern" on T2-weighted images; this pattern consists of a combination of (1) hyperintense fluid within cystic components, with or without fluid levels, (2) intermediate signal tissue similar in intensity to that of muscle, and (3) slightly hypointense tissue similar in intensity to that of fibrous tissue.
Apposition to bone surfaces without a clear plane of separation is seen in 50-59% of cases (see Image 12), with clear bone erosion or destruction in 22% (see Image 2). Calcifications are not easily seen on MRIs and, when visible, are usually hypointense on all sequences (see Image 3).
The use of gadolinium-based contrast agents has a limited value in the evaluation of synovial sarcomas. On dynamic imaging, malignant soft-tissue masses have been shown to enhance earlier, faster, and more predominantly peripherally than benign lesions.10 These findings are believed to be secondary to the effects of tumor angiogenesis. Synovial sarcomas usually demonstrate heterogeneous contrast enhancement, with early enhancement of tumor within 7 seconds of arterial enhancement.10 Gadolinium-based agents may be helpful in posttreatment MRIs, in which mild, diffuse, nonfocal contrast enhancement is a typical finding. With recurrent disease, focal nodules with homogeneous enhancement and high signal intensity without cystic components are typically seen on T2-weighted images.
Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. As of late December 2006, the FDA had received reports of 90 such cases. Worldwide, over 200 cases have been reported, according to the FDA. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see the FDA Public Health Advisory or Medscape.
False Positives/Negatives
Synovial sarcoma tumors can appear small, especially those in the hands or head and neck regions,2,8,11 where they come to medical attention earlier. Often, the small size, well-defined margins, and sometimes homogeneous appearance of synovial sarcoma can lead to misdiagnosis as a benign lesion. Berquist et al found that synovial sarcoma was the malignant soft-tissue sarcoma most frequently misdiagnosed as benign.12 Small, superficial, solid lesions should be approached as a possible sarcoma unless strong signs prove otherwise.5,13
Ultrasonography
Findings
Ultrasonography does not play a significant role in the evaluation of synovial sarcomas. The imaging characteristics cannot be used to establish a precise diagnosis. Grossly, sonograms can provide information regarding the size and consistency of a soft-tissue mass (eg, differentiating cystic from solid masses or a localized mass from diffuse edema). Most commonly, a well-circumscribed, heterogeneous mass, with or without cystic components, is seen.
Ultrasonography can be useful as a real-time imaging technique for guiding diagnostic needle biopsy, especially in large heterogeneous tumors.14 Color-flow Doppler ultrasound imaging reveals blood flow in solid soft-tissue masses.14
Degree of Confidence
Studies have shown that color-flow Doppler ultrasound findings are not specific for differentiating benign from malignant tumors; however, the technique may be useful for monitoring the regression of tumor neovascularity after the administration of chemotherapy or irradiation.
Nuclear Imaging
Findings
Nuclear medicine does not play a significant role in the workup of synovial sarcoma. Positron emission tomography or bone scanning can be used for the evaluation of skeletal or lung metastases or recurrent disease.
Angiography
Findings
Angiography does not play a significant role in the evaluation of synovial sarcoma. Angiography allows the gross evaluation of the tumor's size and vascularity. The tumor appears as a soft-tissue mass with a fine network of tumor vessels and an inhomogeneous capillary blush. The degree of vascularity may vary according to the histopathology. One study reported that monophasic tumors of synovial sarcoma demonstrate a higher degree of neovascularity than biphasic tumors.15
More on Synovial Sarcoma |
| Overview: Synovial Sarcoma |
 Imaging: Synovial Sarcoma |
| Follow-up: Synovial Sarcoma |
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References
Murphey MD, Gibson MS, Jennings BT, et al. From the archives of the AFIP: Imaging of synovial sarcoma with radiologic-pathologic correlation. Radiographics. Sep-Oct 2006;26(5):1543-65. [Medline].
Nakajima H, Matsushita K, Shimizu H, et al. Synovial sarcoma of the hand. Skeletal Radiol. Nov 1997;26(11):674-6. [Medline].
Ladanyi M. Fusions of the SYT and SSX genes in synovial sarcoma. Oncogene. Sep 10 2001;20(40):5755-62. [Medline].
Fisher C. Synovial sarcoma. Ann Diagn Pathol. Dec 1998;2(6):401-21. [Medline].
Ferrari A, Gronchi A, Casanova M, et al. Synovial sarcoma: a retrospective analysis of 271 patients of all ages treated at a single institution. Cancer. Aug 1 2004;101(3):627-34. [Medline].
American Joint Committee on Cancer. What is cancer staging?. Available at http://www.cancerstaging.org/mission/whatiscs.html. Accessed July 11, 2007.
Lewis JJ, Antonescu CR, Leung DH, et al. Synovial sarcoma: a multivariate analysis of prognostic factors in 112 patients with primary localized tumors of the extremity. J Clin Oncol. May 2000;18(10):2087-94. [Medline].
Hirsch RJ, Yousem DM, Loevner LA, Montone KT, Chalian AA, Hayden RE. Synovial sarcomas of the head and neck: MR findings. AJR Am J Roentgenol. Oct 1997;169(4):1185-8. [Medline]. [Full Text].
Jones BC, Sundaram M, Kransdorf MJ. Synovial sarcoma: MR imaging findings in 34 patients. AJR Am J Roentgenol. Oct 1993;161(4):827-30. [Medline]. [Full Text].
van Rijswijk CS, Hogendoorn PC, Taminiau AH, Bloem JL. Synovial sarcoma: dynamic contrast-enhanced MR imaging features. Skeletal Radiol. Jan 2001;30(1):25-30. [Medline].
Rangheard AS, Vanel D, Viala J, et al. Synovial sarcomas of the head and neck: CT and MR imaging findings of eight patients. AJNR Am J Neuroradiol. May 2001;22(5):851-7. [Medline]. [Full Text].
Berquist TH, Ehman RL, King BF, Hodgman CG, Ilstrup DM. Value of MR imaging in differentiating benign from malignant soft-tissue masses: study of 95 lesions. AJR Am J Roentgenol. Dec 1990;155(6):1251-5. [Medline]. [Full Text].
Spillane AJ, A'Hern R, Judson IR, Fisher C, Thomas JM. Synovial sarcoma: a clinicopathologic, staging, and prognostic assessment. J Clin Oncol. Nov 15 2000;18(22):3794-803. [Medline]. [Full Text].
Van der Woude HJ, Vanderschueren G. Ultrasound in musculoskeletal tumors with emphasis on its role in tumor follow-up. Radiol Clin North Am. Jul 1999;37(4):753-66. [Medline].
Lois JF, Fischer HJ, Mirra JM, Gomes AS. Angiography of histopathologic variants of synovial sarcoma. Acta Radiol Diagn (Stockh). Jul-Aug 1986;27(4):449-54. [Medline].
Torriani M, Etchebehere M, Amstalden E. Sonographically guided core needle biopsy of bone and soft tissue tumors. J Ultrasound Med. Mar 2002;21(3):275-81. [Medline].
Gil-Sánchez S, Marco-Doménech SF, Irurzun-López J, et al. Ultrasound-guided skeletal biopsies. Skeletal Radiol. Nov 2001;30(11):615-9. [Medline].
Jelinek JS, Murphey MD, Welker JA, et al. Diagnosis of primary bone tumors with image-guided percutaneous biopsy: experience with 110 tumors. Radiology. Jun 2002;223(3):731-7. [Medline]. [Full Text].
Andrassy RJ, Okcu MF, Despa S, Raney RB. Synovial sarcoma in children: surgical lessons from a single institution and review of the literature. J Am Coll Surg. Mar 2001;192(3):305-13. [Medline].
Canale ST, Daugherty K, Jones L, eds. Campbell's Operative Orthopaedics. 9th ed. St Louis, Mo: Mosby-Year Book; 1998.
Dupuy DE, Rosenberg AE, Punyaratabandhu T, Tan MH, Mankin HJ. Accuracy of CT-guided needle biopsy of musculoskeletal neoplasms. AJR Am J Roentgenol. Sep 1998;171(3):759-62. [Medline].
Einhorn TA, Nielsen GP. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 1-2001. A 26-year-old man with a mass in the knee. N Engl J Med. Jan 11 2001;344(2):124-31. [Medline].
Ilaslan H, Sundaram M. Advances in musculoskeletal tumor imaging. Orthop Clin North Am. Jul 2006;37(3):375-91, vii. [Medline].
Klijanienko J, Caillaud JM, Lagacé R, Vielh P. Cytohistologic correlations in 56 synovial sarcomas in 36 patients: the Institut Curie experience. Diagn Cytopathol. Aug 2002;27(2):96-102. [Medline].
Kransdorf MJ. Malignant soft-tissue tumors in a large referral population: distribution of diagnoses by age, sex, and location. AJR Am J Roentgenol. Jan 1995;164(1):129-34. [Medline]. [Full Text].
Matsuzaki A, Suminoe A, Hattori H, Hoshina T, Hara T. Immunotherapy with autologous dendritic cells and tumor-specific synthetic peptides for synovial sarcoma. J Pediatr Hematol Oncol. Mar-Apr 2002;24(3):220-3. [Medline].
McCarville MB, Spunt SL, Skapek SX, Pappo AS. Synovial sarcoma in pediatric patients. AJR Am J Roentgenol. Sep 2002;179(3):797-801. [Medline]. [Full Text].
Oda Y, Hashimoto H, Tsuneyoshi M, Takeshita S. Survival in synovial sarcoma. A multivariate study of prognostic factors with special emphasis on the comparison between early death and long-term survival. Am J Surg Pathol. Jan 1993;17(1):35-44. [Medline].
Parkkola RK, Mattila KT, Heikkilä JT, et al. Dynamic contrast-enhanced MR imaging and MR-guided bone biopsy on a 0.23 T open imager. Skeletal Radiol. Nov 2001;30(11):620-4. Epub 2001 Sep 22. [Medline].
Ruddy S, Harris ED Jr, Sledge CB, eds. Kelley's Textbook of Rheumatology. 6th ed. Philadelphia, Pa: WB Saunders Co; 2001.
Sandberg AA, Bridge JA. Updates on the cytogenetics and molecular genetics of bone and soft tissue tumors. Synovial sarcoma. Cancer Genet Cytogenet. Feb 2002;133(1):1-23. [Medline].
Valenzuela RF, Kim EE, Seo JG, Patel S, Yasko AW. A revisit of MRI analysis for synovial sarcoma. Clin Imaging. Jul-Aug 2000;24(4):231-5. [Medline].
Further Reading
Keywords
synovioma, lower extremity carcinoma, synovial cancer, cancer of the lower extremities, musculoskeletal tumor, cancer of the upper extremities, t(X;18) translocation mutation, SYT gene, SSX1 gene, SSX2 gene
