Abstract
Neuroendocrine (NE) carcinoma of the breast is extremely rare and constitutes less than 0.1% of all breast tumors. Only a few studies are currently available in the literature and a standard approach to treating this tumor has yet to be established. The aim of this study was to apply pathological treatment modalities in clinical practice and to select the most appropriate treatment accordingly. Six female patients were diagnosed with primary NE carcinoma of the breast. The patients underwent modified radical mastectomy with axillary dissection. Pathological specimens were stained with hematoxylin and eosin and an immunohistochemical panel of antibodies [neuron-specific enolase (NSE), chromogranin, synoptophysin, estrogen and progesterone receptor, c-erbB2 and Ki-67]. The results showed that tumor size ranged from 2 to 4.5 cm in diameter. Lymph node metastasis was detected in 4 (67%) patients. Estrogen and progesterone receptor expression was found in 5 (83%) patients. None of the patients expressed c-erbB2. Chromogranin was found to be positive in 5 (83%) patients. Synoptophysin expression was detected in 5 (83%) patients. NSE was stained in 4 (67%) patients. An intraductal component was found in 5 (83%) patients. Lymphovascular invasion was found in 5 (83%) patients. Adjuvant chemotherapy was administered to patients with a Ki-67 index of ≥10%. Radiotherapy was administered to 4 (67%) patients, and 4 (67%) patients received hormonal therapy. The mean follow-up time was 31.1 months (range 12-52). All 6 patients survived, although following chemotherapy and tamoxifen, the disease progressed in 1 patient who received second-line hormonal therapy. In conclusion, NE carcinoma of the breast is a distinct entity. Management of this rare tumor may include surgery and radiotherapy depending on the size of the tumor and lymph node status. However, the exact role of chemotherapy and hormonal therapy has yet to be established. Adjuvant chemotherapy is recommended for patients with a Ki-67 index of ≥10%, and hormonal treatment appears to be feasible in patients who are positive for estrogen and/or progesterone receptor.