Leptomeningeal plasmacytosis. Case report and considerations on treatment.

We describe a 68-year-old patient with a plasma cell leukaemia in haematological remission presenting with massive intracranial leptomeningeal plasmocytic infiltration (LPI) and hydrocephalus. He was treated with skull irradiation and a combination of intraventricular and lumbar intrathecal therapy with methotrexate. Neurologic improvement and clearance of plasma cells from the cerebrospinal fluid was reached after 2 weeks of treatment but prolonged follow-up was interrupted by a lethal gastro-intestinal haemorrhage, 6 weeks after starting the therapy. From previously reported cases it is known that LPI almost always occurs in either high-grade plasmocytomas or plasma cell leukaemia. These data suggest that therapy of LPI should be the same as in other leukaemias with leptomeningeal infiltration.