Metastatic small cell neuroendocrine carcinoma of the breast.

Cutaneous metastases from internal malignancies in women overwhelmingly emanate from the breast and typically exhibit features of an adenocarcinoma, although other histopathologic patterns may also be seen. Neuroendocrine breast carcinoma represents an uncommon variant of mammary carcinoma with fewer than 40 cases of the small cell subcategory reported. As with other small cell carcinomas, they may exhibit Merkel cell-like features and appropriate diagnosis of these tumor deposits often turns on clinical history and an appropriate immunohistochemical profile. Herein, we report the first known patient with cutaneous metastases from a small cell neuroendocrine breast carcinoma.