Abstract Acinic cell carcinoma of breast is a rare subtype of triple negative breast carcinoma and demonstrates extensive morphologic overlap with acinic cell carcinoma of the salivary gland. In this study, we perform a detailed morphologic and immunohistochemical description of two cases of this rare entity, and undertake a comprehensive review of all reported cases of breast acinic cell carcinoma in the English language literature to date. One third of reported cases of breast acinic cell carcinoma have been associated with the presence of a ductal carcinoma not otherwise specified (NOS) component, which is frequently poorly differentiated. Breast acinic cell carcinoma can demonstrate focal morphologic features similar to microglandular adenosis; these areas are frequently negative for collagen IV and laminin on immunohistochemistry. The true relationship between these two entities remains unclear, but we advocate that microglandular adenosis-like areas at the periphery of a breast acinic cell carcinoma should be considered part of the carcinomatous process and re-excised if this process extends to the initial surgical margins.