Solitary meningeal plasmacytoma: Report of a case with electron microscopic and immunohistologic observations.

An unusual case of solitary extraskeletal plasmacytoma (SEP) arising from the meninges of the anterior fossa in a 58-year-old woman is presented. Despite an apparently complete surgical excision and 5000 rads to the tumor area given postoperatively, a recurrence ensued 5 years later. During the 5 years of clinical observation, repeated serum electrophoresis and immunoelectrophoresis, bone surveys, and bone marrow aspirations have ruled out the presence of underlying multiple myeloma. Immunofluorescence studies of the recurrent tumor showed the neoplastic cells to be producing a monoclonal immunoglobulin (IgA, kappa). Ultrastructural examination showed neoplastic plasma cells with marked nucleocytoplasmic asynchrony, frequent cytoplasmic electron-dense bodies, and rough endoplasmic reticulum dilated and filled with with electron-dense material. A critical evaluation of the eight cases of intracranial SEP published in the literature revealed that only three are well-documented examples of this tumor.