Extramedullary plasmacytoma of the breast simulating breast cancer.

A patient with a palpable mass in the breast suggestive of carcinoma underwent radical modified mastectomy. Surprisingly, histology of the tumor revealed an extramedullary plasmacytoma. Further diagnostic work up showed no evidence of underlying multiple myeloma. Among neoplastic lesions of the breast, although rare, malignancy of mesenchymal or lymphoproliferative origin should always be considered.