Purpose of review: Breast cancer is a collection of diseases including the more common invasive ductal and lobular carcinomas and rarer subtypes of breast cancer. This review summarizes the features of rare breast cancers.
Recent findings: Each of the rare tumors has defined pathological and clinical features that impact treatment recommendations. In this review, we summarize these for each rare type of breast cancer and where available we include molecular features of each tumor. Rare subtypes of breast cancer each have unique features. In many cases, data is limited for the optimal treatment approaches.
Keywords: Breast cancer; Rare breast cancer subtypes.