Abstract
primary neuroendocrine carcinomas of the breast represent a minority and are currently included in the latest WHO classification of breast tumors. Their morphological and immunohistochemical features (chromogranin and synaptophysin expression) allow the retain the diagnosis. we report a case of primary neuroendocrine carcinoma of the breast in 50 years old Moroccan women who presented nodule 4,2 cm palpable and mobile of the left breast. Lumpectomy axillary lymph node resection was performed. a histopathological examination disclosed the diagnosis of primary breast neuroendocrine tumors with negative surgical margins and positive lymph nodes (13 N+/19 N). The tumor cells were positive for neuroendocrine markers, a highKi67 proliferation index and the membrane expression of the invasive tumor cells to the anti-HER2 antibody was 2, a FISH done which was equivocal. Our patient received 6 courses of chemotherapythen radiotherapy; currently she received adjuvant hormonal treatment with Tamoxifene.