Abstract

Background: Neuroendocrine Neoplasms of Breast (NENB) is a rare and under recognized subtype of breast neoplasms. The clinical significance, prognostic risk factors and optimal treatment modalities are limited. This study was focused on clinical and pathological features of 27 NENB cases to improve the understanding of these diseases and to further investigate the behavior of these neoplasms and to provide more factual evidence.

Methods: We retrospectively analyzed the clinicopathological features and follow-up data of 27 patients diagnosed with NENB at the First Affiliated Hospital of Bengbu Medical College between February 2003 and February 2015.

Results: The proportion of NENB from all invasive Breast Carcinomas (BC) in our hospital was 0.24% (27/11352). The expression of specific immunohistochemical markers was different: 48.1% cases showed the expression of Chromogranin A (CgA) (13/27), CD56 was positive in 77.8% cases (21/27), the positive rate of INSM1 and Synaptophysin (Syn) were 85.2% (23/27) and 100.0% (27/27). NENB occurred in older patients (median age, 64). 11 cases (40.7%) were well-differentiated NETs and 16 cases (59.3%) were poorly differentiated NEC. In NETs, The positive rate of ER was 10/11 (90.9%), while in NECs, The positive rate of ER was 9/16 (56.3%), On the basis of immunophenotypes, most of NENBs were of the luminal molecular subtype, 6 cases were luminal A and 15 cases were luminal B, 6 cases were Triple Negative Breast Cancer (TNBC) and had no HER-2 overexpression subtypes.

Conclusion: NENB more likely occurs in elderly patients. Well-differentiated NETs are more often positive for hormone receptors than poorly differentiated NEC. NENBs are almost negative for HER-2. The combination of INSM1 is an effective supplement and improvement for traditional neuroendocrine markers.

Keywords: Breast; Neuroendocrine neoplasm; Clinicopathologic features; Treatment; Prognosis