Adenoid cystic carcinoma of the breast: report of a case.

Adenoid cystic carcinoma of the breast is an uncommon form of cancer, and only a few articles have described the cytological findings of this disease. We report herein the case of a 48-year-old woman who presented with a breast mass beneath the nipple, the aspirate from which consisted of globules of mucous balls surrounded by epithelial cells with scant cytoplasm and hyperchromatic nuclei. Microscopically, the tumor was formed by myoepithelial cells and glandular epithelial cells in a biphasic pattern. Immunohistochemical study revealed positivity for smooth muscle actin. A left total mastectomy with axillary lymph node dissection was performed. None of the 22 axillary lymph nodes contained metastases, and the patient remains well and free from recurrence 29 months after her operation. This case report provides some information about the cytological diagnosis and the accuracy of fine-needle aspiration, which must be considered despite the rarity of this disease.