Meningeal involvement in multiple myeloma.

Meningeal involvement in multiple myeloma is a rare occurrence. We report a case of IgG myeloma with neoplastic cell infiltration into the cerebrospinal fluid as determined by a protein A plaque-forming cell assay. Electrophoresis of the cerebrospinal fluid revealed a monoclonal band in the same position as the monoclonal band in the serum. Meningeal involvement may probably be more common at the terminal stage in multiple myeloma than has been previously considered.