Primary neuroendocrine carcinoma of the breast: a 5-year experiences.

Purpose: Breast neuroendocrine carcinomas constitute approximately 0.3-0.5% of all breast cancers. In this study, we aimed to evaluate the data of patients diagnosed with primary breast neuroendocrine carcinoma.

Methods: Patients with more than 50% neuroendocrine differentiation identified in the histopathological examination between January 2010 and January 2015 and who had no other focus on imaging were evaluated retrospectively from the hospital registry system. Patients with secondary neuroendocrine tumor of the breast and male patients were excluded from the study. All patients gave informed consent. Patients were staged according to TNM classification.

Results: During the study period, 425 patients were operated for breast cancer. Eleven patients were included in the study. The mean age of the patients was 68 (range 49-86). Immunohistochemical examinations revealed positive staining with neuron-specific enolase, synaptophysin and chromogranin in all patients. Ten patients had strong positive estrogen and progesterone receptors and receptor status was not specified in one patient. Distant organ metastasis was detected in 1 patient during the follow-up period, no local recurrence and mortality were seen in any patient.

Conclus On: The most widely used specific markers of neuroendocrine differentiation are chromogranin and synaptophysin. There is no standard treatment protocol for primary breast neuroendocrine tumors. Most of the treatments reported in the literature and in this study are breast sparing surgery or mastectomy, followed by anthracycline and taxanebased chemotherapy and/or hormonotherapy, similar to the treatment of ductal carcinoma. The distinction of primary metastases in breast neuroendocrine tumors is important, so the presence of neuroendocrine tumors should be investigated in other organs. In this case the treatment is changed. The issue of how neuroendocrine differentiation affects clinical outcome is yet to be debated.

Key Words: Chromogranin, Neuroendocrine tumor, Synaptophysin.