Abstract

An infarcted intraductal breast tumor was excised from a woman in her 60s. The tumor was reduced in size from 15 x 8 mm to 6 x 6 mm one month after the fine needle aspiration biopsy. The necrosis was considered to be caused by an infarction and an immunohistohemical analysis revealed positive immunoreactivity of smooth muscle actin of myoepithelial cells that indicated a two-cell layer of tumor cells in the necrosis. Although this necrotic tumor was diagnosed as an infarcted intraductal papilloma by histological examination, its diagnosis was more difficult as it showed partial necrosis by cytological examination alone.