Unsuspected multiples myeloma presenting as bilateral pleural effusion - a cytological diagnosis.

Background: Multiple Myeloma presenting as a pleural effusion is extremely rare. It is usually a late complication and is associated with a poor prognosis.

Methods: A 40-year-old male presented with dyspnea and fever of six months duration. Clinical diagnosis of pulmonary tuberculosis was considered. X-ray chest showed bilateral pleural effusion. Pleural cytology revealed numerous plasma cells, some of which were binucleated and atypical. Cytological differential diagnosis included: Myelomatous effusion and Non-Hodgkin's Lymphoma deposit (Immunoblastic type). Bone marrow biopsy, serum protein electrophoresis and bone scan confirmed the diagnosis of multiple myeloma (Plasmablastic type).

Conclusions: Myelomatous pleural effusion as an initial presentation although extremely rare, should always be considered in presence of atypical plasma cells irrespective of age.