Intracranial metastasis from synovial sarcoma.

Synovial sarcomas comprise between 5% to 10% of all soft tissue sarcomas in adults. It has a predilection for young adults and is one of the more frequently misdiagnosed soft tissue sarcomas. It is not unusual for synovial sarcoma to present initially after a traumatic event. It most commonly occurs in close proximity to a large joint. The most common site for metastasis is the lung, followed by lymph node involvement. Synovial sarcoma rarely metastasizes to the skeleton and when it occurs, it most commonly involves the long bones. Cranial metastasis is rare and has only been described in 2 previously reported cases. Reports of other sarcomas having intracranial metastasis include rhabdomyosarcoma, angiosarcoma, fibrosarcoma, liposarcoma, Ewing's sarcoma, and clear cell sarcoma from the kidney. The synchronous or metachronous development of >or=2 primary soft tissue sarcomas has been reported. These are primary soft tissue sarcomas occurring at multiple soft tissue sites without pulmonary or lymphatic involvement. It is often difficult to distinguish between the synchronous or metachronous appearance of a second primary and soft tissue sarcoma metastasis. This article presents a case of a 17-year-old adolescent boy who presented with simultaneous enlarging masses involving the skull and thigh. Open biopsies confirmed synovial sarcoma in both regions. Staging studies, including computed tomography (CT) of his chest, abdomen/pelvis and bone scan were otherwise negative for metastasis.