Breast adenomyoepithelioma diagnosed on core needle biopsy: a diagnostic challenge

Adenomyoepithelioma represents a rare tumor of the breast characterized by biphasic proliferation of epithelial and myoepithelial cells. Owing to its nonspecific clinical presentation, the rarity, and the morphological pitfalls in differential diagnosis, the diagnosis may be extremely difficult especially on limited samples such as core needle biopsy; thus, the diagnosis is histological, which is confirmed by the specificities of the immunohistochemical analyses. Here we report a case of a 64-year-old female who presented a benign adenomyoepithelioma diagnosed on core needle biopsy, review the clinicopathological features of breast adenomyoepithelioma diagnosed on core needle biopsy, and discuss the useful clues to prompt accurate diagnosis.