Small cell neuroendocrine carcinoma of the breast: a report of three cases and review of the literature.

Small cell neuroendocrine carcinoma of the breast is a rare tumour with less than 30 cases reported in the literature. The clinicopathological findings of three cases of primary neuroendocrine carcinoma of the breast and a review of the pertinent literature are presented. The morphological and immunohistochemical patterns of this tumour are similar to its pulmonary counterpart. Expression of neuroendocrine markers is inconsistent, so morphology is the mainstay of diagnosis. Size is a very important prognostic factor in this tumour, as in breast carcinomas of the usual type.