Primary acinic cell carcinoma of the breast: A case report and literature review.

Acinic cell carcinoma (ACCA), a type of malignant epithelial neoplasm, tends to occur in the parotid gland, and is occasionally found within the breast. Published literature regarding primary ACCA of the breast is scarce, and the number of reports may be fewer than 100. At present, full clinical details have not been published. As an extremely rare disorder, ACCA cannot be definitively diagnosed depending on microscopic structure alone and often requires the assistance of immunohistochemistry. Currently, universal therapies are not available. Here, we present a 47-year-old patient with a history of a palpable mass in the outer upper quadrant of the left breast for more than 2 years, which had obviously increased in size in the last half year. This patient was definitively diagnosed with primary ACCA of the breast. Neoadjuvant chemotherapy was performed preoperatively, and drug sensitivity tests based on primary tumor cells were conducted after surgery and successfully screened chemotherapy schemes for the patient's greater benefit. The whole treatment course followed the guidelines for invasive breast cancer. The patient was free of symptoms for 14 months after surgery. Long-term follow-up is in progress. Altogether, to further broaden the understanding of primary ACCA of the breast, we detail the diagnosis and treatment of one patient and review the relevant literature.