Meningeal involvement in multiple myeloma: report of a case with cytologic and immunocytochemical diagnosis.

Multiple myeloma (MM) with meningeal involvement is a very rare phenomenon. Only 37 cases of plasma cell neoplasia (MM and plasma cell leukemia) with meningeal involvement have been reported.A 60-year-old male with stage IIIA light lambda chain MM returned nine months after the diagnosis with back pain, lower right extremity paresthesias and gait disturbance. A lumbar puncture revealed atypical plasma cells in the cerebrospinal fluid (CSF), and immunocytochemical studies showed a cytoplasmic monoclonal light lambda chain. A diagnosis of myelomatous meningitis was made, and the patient received intrathecal chemotherapy and craniospinal irradiation. He died six months after the diagnosis of meningeal disease.The present case and a review of the literature show that clinical manifestations of meningeal myeloma are non-specific. MM with meningeal involvement is accompanied frequently by circulating atypical plasma cells or plasma cell leukemia. Atypical plasma cells in the CSF are an important finding for the diagnosis of meningeal myeloma, and their neoplastic nature can be best identified by immunocytochemical analyses. Patients with meningeal myelomatosis can have a good response to treatment initially, but their prognosis is poor