An Unusual Case of Primary Small Cell Neuroendocrine Carcinoma of the Breast

: Primary small cell neuroendocrine carcinoma of breast is a rare entity, with only case reports in literature. Histologically, these tumors are similar to small cell carcinoma of the lung with some evidence of ductal carcinoma‐in‐situ with areas of ductal, lobular, or papillary differentiation. Immunoreactivity for neuroendocrine markers is present in two thirds of cases, while 33–50% are positive for estrogen receptor or progesterone receptor. Her2/neu expression has not been reported in small cell carcinoma of the breast. Here we are presenting 53‐year‐old women with locally advanced primary small cell neuroendocrine carcinoma of breast. We will discuss clinicopathological findings, treatment options, prognosis and review of the literature on primary small cell carcinoma of breast.