Abstract: Breast neuroendocrine neoplasm is a heterogeneous tumor group, which includes both breast neuroendocrine neoplasms and invasive breast carcinomas with neuroendocrine differentiation. Since the 1960s, the definition and diagnostic criteria of breast endocrine carcinoma have changed repeatedly. Owing to the lack of a strict definition, the diagnostic terminology for such tumors is unclear and controversial. The fifth edition of the WHO classification of breast neoplasms proposes a new diagnostic criterion for breast neuroendocrine neoplasms. This article reviews the revisions of the pathological definition and diagnostic terms, classification and pathological-morphological characteristics and immune markers, molecular genetic changes, clinical features and treatment, and prognosis of primary breast neuroendocrine neoplasms and some existing issues. As lots of issues about primary breast neuroendocrine neoplasms remain unresolved, formulating specifications is suggested for using relevant diagnostic terms; conducting multicenter, stratified standardized studies on invasive breast cancer with neuroendocrine differentiation; and conducting in-depth studies on primary breast neuroendocrine neoplasms.