Neuroendocrine neoplasms of gastro intestinal tract with special reference to immunohistochemistry markers at a tertiary care hospital

Abstract

: Neuroendocrine neoplasms (NEN) are rare entity comprising ~2% of all malignancies with the gastro intestinal tract (GIT) and the lung being the most common sites. They are classified as epithelial and non epithelial based on their origin. The epithelial type arise from epithelial neuroendocrine progenitor cells and non-epithelial type are derived from the neural crest. According to the latest WHO classification 2022, NEN are categorized into neuroendocrine tumors (NET), neuroendocrine carcinoma (NEC) and mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). The above-mentioned classification is possible with the help of use of immunohistochemistry neuroendocrine markers namely synaptophysin, chromogranin-A and proliferation marker as ki67. Synaptophysin is entirely sensitive, and less specific. Chromogranin A is an excellent marker to follow tumour progression and recurrence but is less useful for the diagnosis as it can be elevated for multiple reasons and is therefore nonspecific but very sensitive.: This study includes 25 cases, with study duration of 2 years including all the cases of neuroendocrine tumours of gastrointestinal tract excluding pancreas. Routine H&E staining was done followed by Immunohistochemical markers consisting of synaptophysin, chromogranin-A and ki67 markers. In our study the affected mean age was 51.8 and there was slight male predominance (1.2:1). The most common site being duodenum followed by stomach, and least affected was oesophagus. Out of total 25 cases of Neuroendocrine neoplasms, 18 cases (72% were diagnosed as NET, which were further categorized into G1 (32%), G2(28%) and G3(12%). Neuroendocrine carcinoma was seen in 04 cases (16%) and 03 cases were of MiNEN.: The GI-NETs are rare but their incidence and prevalence have been increasing. Due to the improvement and advancement in the diagnostic tools and the knowledge about these tumors has helped in diagnosing more of these tumors early and accurately. For accurate grading and pathological diagnosis. It is important to carefully evaluate hot spots for the Ki-67 index, identify areas of the highest mitotic density for mitotic count, and recognize the characteristic histological features of GI-NETS.