Neuroendocrine Differentiated Breast Cancer Cases: A Retrospective Analysis and Literature Review

OBJECTIVES: Neuroendocrine breast carcinoma (NEBC) is a rare subgroup of breast cancer, which makes up 2–5% of all invasive breast cancers. The aim of this retrospective analysis is to present and analyze our own data of primary NEBCs. METHODS: We retrospectively analyzed clinical, pathological, and radiological characteristics of 36 patients diagnosed with neuroendocrine differentiated breast cancer between 2008 and 2019 compared to that of 925 patients with invasive ductal carcinoma (IDC/NOS) along with a literature review. RESULTS: In this study, 36 patients with neuroendocrine differentiated breast carcinoma and 961 patients with (IDC/NOS), as the comparison group, were identified between 2008 and 2019. In NEBC patients, seven were premenopausal and 29 postmenopausal. Patients whose ultrasound (USG), magnetic resonance, and mammographic (MMG) images available in our hospital, high-density masses were detected in the MMG with irregular (77%), microlobulated (80%) and spiculated margins (63%), unaccompanied by asymmetry and structural distortion. Calcifications were less common than invasive breast cancer, present only in four patients (17%). When NEBC were compared to ductal carcinomas (n=925), NEBC were more often human epidermal growth factor receptor 2 negative (p=0.039), estrogen receptor positive (p=0.05), progesterone receptor positive (0.03), and the NEBC patients were older (p=0.02). Age, grade, metastatic status, lymph node number, and molecular type were identified as prognostic factors that significantly affect survival in both groups (p<0.05). CONCLUSION: NEBC is a subtype that is both histopathologically and radiologically distinct from other breast cancer subtypes, and neuroendocrine differentiation may be an important predictive marker in the future.