Clinicopathological Study of Neuroendocrine Carcinoma of the Breast

Introduction: Neuroendocrine carcinoma (NEC) occurs mostly in the digestive organs,such as the pancreas and gastrointestinal tract, and the lungs. Primary NEC of the breast is arare entity. There are not many studies on this disease, and this study wascarried out in order to know the clinical pathology of this disease. Methods:Of 2354 patients who underwent surgery for breast cancer in our hospital duringthe period from January 2000 to July 2015, 8 (0.34%) were pathologicallydiagnosed with NEC of the breast. This study is retrospectively registered. Result:The histological types were small cell carcinoma in one patient and invasiveductal carcinoma (IDC) withneuroendocrine differentiation in the remaining 7. The mean patient age wasslightly higher than that of patients with usual IDC. On pathologicalexamination, the NEC tumors were more hormone dependent and often HER2 negative, as compared tousual IDC, though there was no significant difference in nuclear grade. Thepatients with NEC of the breast showed positivity for neuroendocrine markers onimmunohistological staining, and had favorable outcomes. Conclusion: NECof the breast is rare, and there is no established consensus regarding the pathologicalsignificance, prognosis, and treatment method. Further accumulation of cases isnecessary.