A case report of primary adenoid cystic carcinoma of the breast

Abstract

A rare special subtype of breast carcinoma, adenoid cystic carcinoma, is characterized by the presence of a dual-cell population. Although breast adenoid cystic carcinoma is triple-negative (neoplastic cells are devoid of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression, and excess basal cell markers) and has basal-like features, the malignancy exhibits an indolent clinical behavior. Identification of this type of cancer is challenging, as its imaging features are not specific. This malignancy can be diagnosed on the basis of the characteristic features observed in fine-needle aspiration (FNA) cytology. In the present case report, an 81-year-old female patient in whom left breast cancer was suggested on the basis of a mammographic abnormality (mass) without microcalcifications was admitted to the Department of Breast Surgery for further examination and treatment. Her radiologic examinations including CT, MRI, and ultrasonography revealed a tumor nodule measuring 12 mm in diameter in the C-area of the left breast. Small and large cell clusters were collected around the mucous material, suggesting adenoid cystic carcinoma. Subsequent histopathological and immunohistochemical (CEA, CK7, c-kit, p63, and α-SMA) examinations of the core-needle biopsy (CNB) specimen and the resected tumor confirmed the cytological diagnosis. Cancer cells were slightly positive for ER and negative for PgR and HER2. No recurrence and metastasis were found after 16 months of follow-up.