Fatal intravascular synovial sarcoma in a 31-year-old woman.

A 31-year-old woman presented with acute right abdominal pain of 5 hours' duration. Imaging studies showed obstruction and dilatation of the inferior vena cava. The patient suffered a cardiopulmonary arrest; during emergency surgery 230 g of "clot-like" material was removed from the inferior vena cava, right heart, and pulmonary arteries. The patient died the following day. Pathologic examination of the resected material showed a biphasic synovial sarcoma. At autopsy only a minimal amount of residual tumor was present in the wall of the inferior vena cava. Tumor embolization from another site was excluded on the basis of radiologic studies and autopsy findings. This appears to be the second reported case of intravascular synovial sarcoma and the first reported case with a fatal outcome.