Solid neuroendocrine carcinoma of the breast: a rare tumor.

Abstract Solid Neuroendocrine carcinoma of the breast (SNECB) is a subtype of primary neuroendocrine carcinoma (NEC) of the breast with several distinctive features. In the present study, the authors report a case of 84-year old woman who was admitted in the hospital with a lump in her right breast. Mammography revealed a well-defined nodule in the outer lower quadrant of her right breast. She underwent lumpectomy and sentinel lymph node biopsy, which showed no metastasis. The histological diagnosis was solid neuroendocrine carcinoma of the breast. Microscopically, the tumor is formed from cells arranged in nests or trabeculae and separated by scant connective tissue. Immunohistochemical staining demonstrates strong positivity for NSE, chromogranin, synaptophysin, ER, and PR. The patient is still alive 14 months after diagnosis. Because of the rarity of this disease, there is no standard treatment protocol and a large variety of chemotherapy protocols have been employed in treating this disease.