Synovial sarcoma Electron microscopic study of a typical case

A case of histologically typical synovial sarcoma has been studied by means of electron microscopy. The more important findings are: 1. the confirmation at the ultrastructural level of the biphasic pattern of the tumor; 2. the presence of a basal lamina between the “epithelial” and the “stromal” part of the tumor; 3. the presence of specialized junctions in the form of desmosomes or maculae adhaerentes between neoplastic cells; these are mostly seen in the epithelial part of the tumor but are not infrequent among stromal cells, and 4. the existence in the extracellular component of the neoplasm of mostly amorphous material, microfibrils, and thin fibrils without periodicity. Only a few mature collagen fibers are seen.