Meningeal involvement in Bence Jones multiple myeloma. A case of Bence Jones kappa multiple myeloma with meningeal involvement in a 64-year-old woman is presented. Three years after the diagnosis of multiple myeloma, gait disturbances developed followed by visual disorders and impaired consciousness. A lumbar puncture revealed numerous atypical plasma cells in the cerebrospinal fluid. Craniospinal irradiation and intrathecal injections of methotrexate, cytarabine, and prednisolone were effective for a short period. At autopsy, the leptomeninges were infiltrated diffusely with atypical plasma cells. A review of the literature showed that multiple myeloma with meningeal involvement is accompanied frequently by circulating atypical plasma cells or plasma cell leukemia. Meningeal involvement is a rare complication and shows poor prognosis in cases of multiple myeloma. 