Early gastric mixed neuroendocrine–non-neuroendocrine neoplasms with endoscopic findings of neuroendocrine cell carcinoma components exposed on the mucosal surface: a case report

Abstract

Background Gastric mixed neuroendocrine–non-neuroendocrine neoplasms are rare malignant tumors. The lack of specific findings makes it difficult to diagnose endoscopically. We report the case of early gastric mixed neuroendocrine–non-neuroendocrine neoplasms treated by endoscopic submucosal dissection. Case presentation An 81-year-old Japanese female underwent esophagogastroduodenoscopy for screening and was treated with endoscopic submucosal dissection for the diagnosis of early gastric cancer. Histopathologically, the lesion was diagnosed as mixed neuroendocrine–non-neuroendocrine neoplasms (tubular adenocarcinoma 2 60%, endocrine cell carcinoma 40%), pT1b(submucosa (SM) 900 μm), pUL(−), Ly(+), v(−), pHM0, pVM0. After additional surgical resection without adjuvant chemotherapy, she has had no recurrences or metastases for 3 years. Conclusions Comparing narrow-band imaging magnified endoscopic findings with pathological findings, the depressed area with a lack of surface structure was consistent with the neuroendocrine cell carcinoma component, while narrow-band imaging magnification findings showed non-network vessels. In this case, we examined endoscopic findings of early stage mixed neuroendocrine—non-neuroendocrine neoplasms in detail and compared it with the pathological findings. We believe that these endoscopic findings contribute to the diagnosis of mixed neuroendocrine–non-neuroendocrine neoplasms and can lead to its early detection.

Deficient Mismatch Repair Proteins in Gastric Mixed Neuroendocrine Non-Neuroendocrine Neoplasm: A Rare Case Report

“…NET grade 2 gastric MiNENs were generally smaller than NEC. In a few recent reports on early gastric MiNENs, the Japanese authors emphasized that the possible existence of a neuroendocrine constituent should be taken into account if there is a loss of surface structure in concavity surrounded by a poorly differentiated adenocarcinoma component [ 24 , 26 ].…”

“…NET grade 2 gastric MiNENs were generally smaller than NEC. In a few recent reports on early gastric MiNENs, the Japanese authors emphasized that the possible existence of a neuroendocrine constituent should be taken into account if there is a loss of surface structure in concavity surrounded by a poorly differentiated adenocarcinoma component [24,26]. Notably, the inability of biopsy tissue samples to represent the heterogeneous components of the tumor accurately lowers the probability of preoperative identification of mixed neoplasm [1-3, 6, 9].…”

Gastric mixed neuroendocrine non-neuroendocrine neoplasms

“…Recent studies have shown that g-MiNENs are derived from a single precursor cell that is doubly differentiated after the onset of carcinogenesis ( 33 ). As demonstrated in some malignancies, poorly differentiated carcinomas may also be transformed into alternative transcriptional programmes induced by cellular plasticity, leading to neuroendocrine differentiation ( 34 ). Several studies have conducted comparisons of the mutational characteristics of NE and non-NE components, revealing a shared mutational foundation as well as distinct mutations unique to each component ( 9 , 35 ).…”