Hemangiopericytoma-like synovial sarcoma of the lumbar spine. Case report.

The purpose of this report is to demonstrate that synovial sarcoma should be included in the differential diagnosis of tumors originating from the lumbar spine, especially if they show hemangiopericytoma-like pathological characteristics. A synovial sarcoma is a mesenchymal spindle cell tumor that displays variable epithelial differentiation including glandular formation. It is unrelated to a synovium. More than 80% of these lesions arise in the deep soft tissue of the extremities. The tumor frequently arises adjacent to joints or tendon sheaths. The authors describe a young woman with a hemangiopericytoma-like tumor of the lumbar spine. During repeated operation, this lesion was shown to be a synovial sarcoma, which had invaded the dura mater. The tumor metastasized to the mediastinum and the intradural cervical spine and, finally, to the brain and the lungs. To the authors' knowledge, this is the first reported case of a synovial sarcoma originating from the lumbar spine.