Extramedullary plasmacytoma presenting with myasthenia gravis and mediastinal mass

A 68-year-old woman presented with myasthenia gravis and an anterior medias tinal mass, which proved to be an extramedullary plasmacytoma in the thymus with associated extracellular light chain deposition. Further specimens re vealed plasma cell proliferation in an internal thoracic lymph node and in a subsequent colectomy specimen, indicating systemic disease. This case dem onstrates the rare association between a plasmacytoma in the thymus and mya sthenia gravis. (C) 2000 by The Society of Thoracic Surgeons.