Fine-needle aspiration diagnosis of plasmacytoma presenting as breast masses in a patient on estrogen therapy for prostate cancer

We describe a 79-yr-old man with a history of androgen-independent metastatic prostate cancer treated with exogenous estrogens presenting with bilateral breast masses associated with bilateral axillary lymphadenopathy. Although the findings on physical examination with the concomitant history of estrogen therapy for metastatic prostate cancer raised the clinical suspicion of breast cancer, fine-needle aspiration (FNA) cytology identified the lesions as multiple myeloma.