Male breast cancer (MBC) is rare, accounting for less than 1% of all breast cancers, but incidence is increasing worldwide. Risk factors include increased longevity, obesity, testicular disease and tumors, and germline BRCA2 mutations. BRCA2 carriers are 80 times more at risk than the general population.
Men tend to develop breast cancer later than women. Histologically, MBC is often grade 2, hormone receptor-positive, HER2-negative, and not a specific type of cancer, although in situ and invasive papillary carcinomas are common. Reporting and staging are similar to breast cancer in women. Metastases in the male breast do occur and must be differentiated from primary carcinomas.
Until recently, MBC was thought to resemble its common ER-positive postmenopausal female counterpart. However, research on MBC and advances in research have revealed significant differences between the two. This review provides an up-to-date overview of the biology, genetics, and histology of MBC compared to breast cancer in women for differential diagnosis using histologic mimics.
