title: Primary acinic cell carcinoma of the breast: a clinicopathological and immunohistochemical study.
abstract: Acinic cell carcinoma of the breast is an extremely rare, malignant neoplasm characterized by widespread acinar cell-like differentiation and clinically low-grade malignancy. Herein, we report a case of acinic cell carcinoma of the breast in a 41-year-old woman. The tumor was poorly demarcated but had a firm consistency. It was removed with lumpectomy, and sentinel lymph node biopsy was performed to check for metastasis. Microscopically, the tumor showed an infiltrative growth pattern with a combination of solid, trabecular, and microglandular areas. Many of the tumor cells had abundant clear vacuolated cytoplasm containing zymogen-typed granules which resemble acinar cells of the salivary glands. The immunohistochemical profile of the tumor was also similar to that of salivary gland acinic cell carcinoma: the tumor cells were positive for amylase, lysozyme, α -1-antichymotrypsin, S-100 protein, and epithelial membrane antigen and negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. She received postoperative chemoradiation therapy and has been well for 3 years since surgery. As studies on large series are lacking, further studies are needed to elucidate the biological characteristics of acinic cell carcinoma of the breast.
authors.affiliation: Departments of Surgery and Pathology, Iida Municipal Hospital, 438 Yawatacho, Iida, Nagano 395-8502, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Shingu
authors.forename: Tokiko
authors.initials: T
authors.lastname: Ito
authors.forename: Gengo
authors.initials: G
authors.lastname: Kaneko
authors.forename: Nobuo
authors.initials: N
authors.lastname: Itoh