Rapidly Progressive Atrial Mass and Cardiac Tamponade

Cardiac involvement in multiple myeloma is rare. We report a rapidly progressive atrial mass and plasma cell–infiltrated pericardial effusion with tamponade. Bone marrow biopsy and plasma immunoelectrophoresis confirmed multiple myeloma (Revised International Staging System Stage III). The patient died within 18 weeks of presentation, suggesting aggressive disease with poor prognosis. (Level of Difficulty: Beginner.)