Молодежный инновационный вестникМолодежный инновационный вестник2415-7805Федеральное государственное бюджетное образовательное учреждение высшего образования "Воронежский государственный медицинский университет имени Н.Н. Бурденко" Министерства здравоохранения Российской Федерации10606Conference ProceedingsNeuroendocrine breast tumors: difficulties in classifying and diagnosing focal neuroendocrine changesDenisovaDarya Evgenyevna<p>student</p>remol_dobronog@mail.ruhttps://orcid.org/0009-0008-3197-3426PobedennayaEkaterina Mikhaylovna<p>student</p>remol_dobronog@mail.ruhttps://orcid.org/0009-0005-0493-6361Petrovsky Medical University "Petrovsky National Research Center of Surgery"3006202514159610103202527032025Copyright © 2025, Denisova D.E., Pobedennaya E.M.2025<p align="left"><span style="font-family: Times New Roman, serif;"><span style="font-size: large;"><em>Neuroendocrine tumors are rare oncological diseases. Their diagnosis is difficult, since the classifications are different and not universal. The only way to confirm the diagnosis of neuroendocrine carcinoma (NEC) is histological examination, which requires the expression of neuroendocrine cell markers. A particular difficulty is the diagnosis of primary breast tumors with focal neuroendocrine differentiation, which is caused by the lack of a formulated approach to differential diagnosis and the rare use of appropriate immunohistochemical markers. The aim of the work was to describe the main approaches to the classification of neuroendocrine neoplasms in the context of describing focally differentiated neuroendocrine tumors of the mammary gland using a clinical case as an example. Biopsy material from the breast area with the neoplasm was processed within the framework of routine histotechnics with hematoxylin and eosin staining followed by evaluation using light microscopy, immunohistochemical study was also carried out with antibodies to estrogen and progesterone receptors, to epidermal growth factor 2, to Ki-67, as well as to synaptophysin, chromogranin A and NCAM. This paper presents a brief overview of neuroendocrine neoplasms, methods of their classification, diagnostic methods, data on the pathogenesis of clinical symptoms and pathomorphology.</em></span></span></p>neuroendocrine tumorneuroendocrine breast carcinomamammary glandнейроэндокринная опухольнейроэндокринная карцинома молочной железымолочная железа1.Bhardwaj N, Rohilla M, Srinivasan R. Neither Russell nor Magenta bodies: A cytological dilemma in breast fine needle aspiration cytology. Cytopathology. 2022;33(5):650-653. doi:10.1111/cyt.131532.La Rosa S, Uccella S. Classification of neuroendocrine neoplasms: lights and shadows. Rev Endocr Metab Disord. 2021;22(3):527-538. doi:10.1007/s11154-020-09612-23.Nagtegaal ID, Odze RD, Klimstra D, et al. The 2019 WHO classification of tumours of the digestive system. Histopathology. 2020;76(2):182-188. doi:10.1111/his.139754.Tan PH, Ellis I, Allison K, et al. The 2019 World Health Organization classification of tumours of the breast. Histopathology. 2020;77(2):181-185. doi:10.1111/his.140915.Gallo M, Campione S, Di Vito V, et al. Primary Neuroendocrine Neoplasms of the Breast: Still Open Issues. Front Endocrinol (Lausanne). 2021;11:610230. Published 2021 Jan 26. doi:10.3389/fendo.2020.6102306.Røge R, Nielsen S, Riber-Hansen R, Vyberg M. Impact of Primary Antibody Clone, Format, and Stainer Platform on Ki67 Proliferation Indices in Breast Carcinomas.