Small-cell breast cancer is a very rare and aggressive type of neuroendocrine carcinoma. Histologically, it is indistinguishable from small-cell neuroendocrine lung cancer. Due to that, patients with small-cell neuroendocrine breast cancer should undergo examination of other areas of the body. Small-cell breast cancer may be treated with a combination of surgery, radiation therapy and chemotherapy. However, no standard treatment exists due to the small number of cases. We present a case of a 49-year-old woman with right breast primary small-cell neuroendocrine carcinoma.