[A Case Report of Adenomyoepithelioma Coexisting with Apocrine Carcinoma in Contralateral Breasts]

Adenomyoepithelioma(AME)of the breast is a rare condition, and comorbidity with carcinoma is even more unusual. Herein, we report a case of both AME and apocrine carcinoma in different breasts of a single patient. A 48-year-old woman presented to our clinic with a right breast tumor. Fine needle aspiration cytology(FNAC)was indeterminate and suspicious for both papilloma and non-invasive ductal carcinoma, but excisional biopsy indicated an AME. Immuno-histochemical staining showed EMA(+), AE1/3(+), and CK7(+)mammary duct cells and αSMA(+), CK5/6(+), and p63(+) myoepithelial cells. Six months later, the patient noticed a left breast tumor, and although FNAC indicated no malignancy, after 6 additional months, the tumor size had increased and a mammography revealed tumor microcalcification, suggesting malignancy. Vacuum-assisted biopsy revealed an apocrine carcinoma. The patient underwent partial mastectomy and sentinel node biopsy, followed by radiotherapy and chemotherapy. The post-surgical pathology was pT1pN0M0, Stage Ⅰ, triple- negative, and the patient was disease-free for 12 years postoperatively. To our knowledge, this is only the second case of AME and breast cancer in different breasts reported in Japan.