Ultrastructure of subcutaneous sacrococcygeal myxopapillary ependymoma.

Electron microscopic examination was performed on three cases of myxopapillary ependymoma that occurred as primary tumors in the skin and subcutaneous tissue of the sacrococcygeal region. Some features found in both normal and neoplastic ependymal cells were observed. These included microvilli, cilia, desmosomal attachments, and cytoplasmic filaments. Other features noted, basement membranes and greatly decreased cilia, are characteristic of myxopapillary ependymomas and normal choroid plexus. In these situations, ependymal cells are apposed to connective tissue. The ependymal nature of this rare tumor is reaffirmed.