Pleural effusion as first sign of extramedullary plasmacytoma.

A patient with mediastinal EP with extension to pleural spaces and subsequent pleural effusion is described. The finding of many plasma cells in pleural fluid led to diagnosis. Similar histologic findings such as multiple myeloma and immunoblastic lymphoma were ruled out by clinical approach and immunochemistry, respectively. This pleural effusion represents the first case described caused by EP.