Plasma cell tumours: cytomorphological features in a series of 12 cases diagnosed on fine needle aspiration cytology

OBJECTIVE: Plasma cell tumours represent autonomous proliferation of plasma cells and can manifest as multiple myeloma, monoclonal gammopathy of undetermined significance, variants of plasma cell myeloma or plasmacytoma. METHODS: We report 12 cases of plasma cell tumours, which were initially diagnosed as plasmacytoma on fine needle aspiration cytology (FNAC). The patients were further subjected to bone marrow examination, serum electrophoresis, urine examination for Bence-Jones proteins, and x-ray examination of the skeleton. RESULTS: The cytological smears from all cases were cellular and showed numerous plasma cells in varying degrees of maturity. Subsequent to investigations, five cases were labelled as multiple myeloma with secondary extramedullary plasmacytoma, three as solitary bone plasmacytoma and two as primary extramedullary plasmacytoma. In the remaining two cases, bone marrow and urine examination findings were not available, so a conclusive diagnosis of multiple myeloma or solitary plasmacytoma could not be made. CONCLUSION: The study highlights the role of FNAC in the diagnosis of plasma cell tumours. Subsequent work-up and follow-up of these patients is important to rule out the presence of multiple myeloma.