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Retroperitoneal synovial sarcoma: a clinicopathological study of 6 cases.

PURPOSE
Synovial sarcoma (SS) arising in the retroperitoneum is a rare tumor. In this location it can be confused with other biphasic tumors and with other spindle and round cell sarcomas. We report 6 cases of SSs with emphasis on their clinicopathological findings.


PATIENTS AND METHODS
Six cases were studied, diagnosed as primary retroperitoneal SSs. Clinical, radiological and pathological findings were included in the study. Follow-up information was available in 5 out of 6 cases.


RESULTS
The cases consisted of 5 males and 1 female (aged 27-42 years, median 34), who complained preoperatively for pain in the abdominal region (n=4) and dysuria (n=2). Clinical examination was negative. Abdominal X-ray showed a suspicious mass in 4 cases and computed tomography (CT) revealed the tumor mass in all cases. Surgical removal of the tumor was performed. Tumors ranged in size from 6.5 to 14 cm (median 11); histologically, all tumors were biphasic and 1 had poorly differentiated areas. Sarcomas were of high grade (n=3) and intermediate grade of malignancy (n=3). Immunohistochemical stains for cytokeratins AE1/AE3, CAM5.2, S-100, CD34, EMA, SMA and CD99 were performed. All tumors recurred or metastasized within the abdomen. Four patients died of disease within 8-38 months.


CONCLUSION
Retroperitoneal SSs are very rare neoplasms that attain a large size, are difficult to excise and recur locally. Metastatic potential is low; however, mortality is very high.