Central nervous system involvement in multiple myeloma: Experience from a tertiary cancer center and review of literature

Background: Multiple myeloma (MM) results from clonal expansion of immunoglobulin secreting, heavy chain class-switched, terminally differentiated B-lymphocytes (plasma cells), resulting in radiologic or biochemical evidence of end-organ damage. Though neurological manifestations (peripheral neuropathies, spinal radiculopathies, cranial nerve palsies, and metabolic encephalopathies) can occur during the disease course, direct central nervous system (CNS) infiltration by malignant plasma cells (CNS-MM) is very rare (~1%) and has a dismal prognosis (survival of <6 months). Methodology: Clinico-laboratory profile and outcome of CNS-MM patients diagnosed and treated at a tertiary cancer care hospital were retrospectively analyzed. Results: On scrutinizing 500 consecutive myeloma case records, 4 patients with CNS-MM were identified. All these patients were diagnosed during myeloma relapse, and all had deceased within 1 week and 12 months of developing CNS infiltration. Our experience with CNS-MM patients is similar to the experiences documented across major world literature. Conclusion: Our manuscript reinforces that CNS-MM should be considered in any myeloma patient presenting with unexplainable CNS manifestations. As there are no prospective studies to recommend optimal treatment strategies, CNS-MM still remains a dismal complication of myeloma.