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

Abstract Purpose: Neuroendocrine breast carcinoma (NEBC) is a rare subgroup of breast cancer, which makes up 2 to 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 2008-2019 compared to that of 925 patients with invasive ductal carcinoma (IDC/NOS) along with a literature review. Result: In this study, 36 patients with neuroendocrine differentiated breast carcinoma and 961 patients with invasive ductal carcinoma (IDC/NOS), as the comparison group, were identified, clinics between 2008-2019 . In NEBC patients, 7 were premenopausal and 29 postmenopausal. Patients whose ultrasound (USG), magnetic resonance (MR), 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 4 patients (17%). When NEBC were compared to ductal carcinomas (n = 925), NEBC were more often HER2 negative (p = 0.039), ER positive (p = 0.05) ,PR 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 will become more predictive in the future.