Abstract
A 72-year-old woman was admitted to our department with a tumor that was 2.2 cm in diameter in her left breast. The tumor was diagnosed as an adenomyoepithelioma because p63-positive fusiform cells were observed in the core needle biopsy specimen. The tumor grew to 4.3 cm in diameter during the follow-up period, and a partial resection of the breast was performed. The tumor was composed of both solid and cystic lesions and mainly consisted of adenomyoepithelioma cells. The central lesion of the tumor was composed of atypical p63-positive cells. Because the lesion also stained positively for p53 and contained mitotic cells and comedo-like necrosis, we concluded that the breast tumor was a myoepithelial carcinoma arising within an adenomyoepithelioma. We have been strictly following the patient, and no signs of recurrence were observed one and a half years after operation. Since myoepithelial carcinoma in the breast is very rare, there is no established strategy for treatment and observation. The patient should be closely monitored after resection of breast myoepithelial carcinoma.
