Cardiac plasmacytoma.

A 69-year-old white woman presented with a 3-month history of progressive dyspnea, orthopnea, fatigue and weakness. Clinical, diagnostic imaging and echocardiographic investigations suggested an occult primary cancer with metastasis to the heart. The patient's condition deteriorated gradually, and she died 2 months later. At autopsy, a malignant tumor encasing the heart and a 1-cm solitary tumor nodule in the lower lobe of the left lung were found. Histologic and electron microscopic studies revealed a plasmacytoma predominantly involving the epicardium and a small solitary plasmacytoma located in the left lung. The two tumors were further confirmed by immunohistochemical studies that showed monoclonal IgG expression and kappa light chain restriction.