EXTRAMEDULLARY PLASMACYTOMAS PRESENTING AS MEDIASTINAL MASSES - CLINICOPATHOLOGICAL STUDY OF 2 CASES PRECEDING THE ONSET OF MULTIPLE-MYELOMA

We present two cases of extramedullary plasmacytoma presenting as a me diastinal mass and preceding the onset of full-blown multiple myeloma. The patients are a 62-year-old woman who presented with progressive d yspnea and left-sided chest pain and a 59-year-old asymptomatic man. I n both patients, radiographic studies revealed a posterior and anterio r mediastinal mass, respectively. Surgical resection of the tumor was performed in the two cases. The tumors were characterized by a well-ci rcumscribed proliferation of plasma cells surrounded by residual lymph nodal tissue. Immunohistochemical studies on paraffin sections demons trated lambda light chain restriction. Follow-up in our patients revea led that both of them developed multiple myeloma after 6 months and 2 years, respectively. One patient received treatment with melphalan and prednisone and is currently alive and well. without evidence of disea se, 2 years after diagnosis. The second patient died 4 years after res ection of his tumor with evidence of disease in lumbar spine, skull, a nd lungs. Extramedullary plasmacytoma presenting as a mediastinal mass may precede the onset of full-blown multiple myeloma; therefore, inst itution of early systemic therapy in these patients may be of value in preventing further progression of the disease.