Small cell neuroendocrine tumor of the breast in a 40 year-old woman: a case report

INTRODUCTION: Small cell neuroendocrine cancer of the breast is a rare tumor with less than 30 cases reported in the literature. The morphological and immunohistochemical patterns of this tumor are similar to small cell neuroendocrine cancer of the lung. For this reason, it is often difficult to distinguish a primary small cell neuroendocrine cancer of the breast from a metastatic lesion from other sites. CASE PRESENTATION: We report and characterize with immunohistochemical techniques a case of primary small cell neuroendocrine cancer of the breast occurring in a 40-year-old Caucasian woman. A palpable and mobile 3.0 cm tumor was located in the upper-outer quadrant of her right breast. Lumpectomy and subsequent radical mastectomy with axillary lymph node resection were performed. Microscopically, the tumor consisted predominantly of a diffuse proliferation of small oat cells. The tumor cells were positive for neuroendocrine markers chromogranin A and synaptophysin. One of 16 lymph nodes was metastatic. A correct treatment needs to be chosen. CONCLUSIONS: It has recently been demonstrated that early small cell neuroendocrine cancer of the breast shows a good prognosis with adjuvant treatments with high disease free survival. Our patient is alive and well without disease eight years after treatment. We performed an adjuvant therapy with the classic scheme doxorubicin and cyclophosphamide, followed by carboplatin and etoposide. A more extensive review is required to define a standard treatment protocol for this rare neoplasm.