A Case of Primary Acinic Cell Carcinoma of the Breast

Abstract

Acinic cell carcinoma (AcCC) of the breast is an extremely rare invasive ductal carcinoma that demonstrates similar morphological features to that of AcCC of the salivary gland, first reported in 1996.

A 68-year-old woman presented to our hospital with a palpable mass in the left breast. Physical examination revealed an irregular mass in the lateral upper quadrant of the left breast, measuring approximately 1 cm in diameter. The tumor was identified as invasive ductal carcinoma by core needle biopsy. Computed tomography showed no other findings in the whole body, including the salivary glands, which were suspected to be malignant. The patient underwent breast-conserving surgery with sentinel lymph node biopsy.

Histopathologically, the tumor cells with oval nuclei and basophilic cytoplasm showed an infiltrating microglandular growth pattern. Immunohistochemically, the tumor cells were positive for S-100, α1-antichymotrypsin, amylase, p53, CEA, EMA, and gross cystic disease fluid protein-15 and negative for mammaglobin, ER, PgR, and HER2. Based on the above results, a diagnosis of AcCC of the breast was made.

Although the patient refused to receive postoperative chemotherapy, there were no signs of recurrence for 4 years and 7 months after surgery.