[Plasmocytic meningitis in multiple myeloma. An anatomo-clinical observation]

A confusional state due to hypercalcemia led to the discovery of multiple myeloma in a 73 year old man. The recurrence of a confusional state, related to plasma cell meningitis called for hospitalization. Serum, urine and cerebrospinal fluid immunoelectrophoresis revealed monoclonal immunoglobulines of lambda light chains. The pathologic study showed an invasion of the subarachnoid space by abnormal plasma cells. The dura mater and brain substance were not invaded. The leptomeningeal invasion by multiple myeloma plasma cells in a rare occurrence. We have found only three such cases published before. The analysis of our case and the three other leads to some comment. The clinical features are those of chronic meningitis revealed by a confusional study or epilepsy. The existence of abnormal plasma cells in the cerebrospinal fluid and their absence in the blood stream seems to suggest a local production of these cells. The histopathological study confirmed, in our case as in the others published, the massive invasion of the subarachnoid space by plasma cells while the dura mater is not invaded.