A patient with lambda light-chains Bence-Jones multiple myeloma (MM) showed a meningeal myelomatosis during a relapse of his illness. Meningeal infiltration was showed through the detection of plasmatic cells in cerebro spinal fluid, identified morphologic and immunophenotypically, together with hyperproteinemia constituted exclusively by lambda light-chains. Treatment was given, intrathecal (methotrexate and cytosine arabinoside) and systemic (vincristine, adriamycin and dexamethasone) chemotherapy, with disappearance of meningeal infiltration. However the patient died, after three months evolution of MM, tough. Literature on this topic is reviewed.