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Abstract Background The clinicopathological features and endoscopic characteristics under magnifying endoscopy with narrow band imaging (ME-NBI) between early-stage gastric-type differentiated adenocarcinoma (GDA) and intestinal-type differentiated adenocarcinoma (IDA) remain controversial. Methods Early gastric adenocarcinomas that underwent endoscopic submucosal dissection (ESD) in Nanjing Drum Tower Hospital between August 2017 and August 2021 were included in the present study. GDA cases and IDA cases were selected based on morphology and immunohistochemistry staining of CD10, MUC2, MUC5AC, and MUC6. Clinicopathological data and endoscopic findings in ME-NBI were compared between GDAs and IDAs. Results The mucin phenotypes of 657 gastric cancers were gastric (n = 307), intestinal (n = 109), mixed (n = 181) and unclassified (n = 60). No significant difference was observed in terms of gender, age, tumor size, gross type, tumor location, background mucosa, lymphatic invasion, and vascular invasion between patients with GDA and IDA. GDA cases were associated with deeper invasion than IDA cases (p = 0.007). In ME-NBI, GDAs were more likely to exhibit an intralobular loop patten, whereas IDAs were more likely to exhibit a fine network pattern. In addition, the proportion of none-curative resection in GDAs was significantly higher than that in IDAs (p = 0.007). Conclusion The mucin phenotype of differentiated early gastric adenocarcinoma has clinical significance. GDA was associated with less endoscopically resectability than IDA.

Abstract Background Small bowel adenocarcinomas (SBAs) are rare and there is little comprehensive data on SBA genomic alterations for Asian patients. This study aimed to profile genomic alterations of SBA in Japanese patients using targeted next-generation sequencing (NGS). Methods We examined 22 surgical resections from patients with primary SBA. SBA genomic alterations were analyzed by NGS. Mismatch repair (MMR) status was determined by immunohistochemical analysis. Mucin phenotypes were classified as gastric (G), intestinal (I), gastrointestinal (GI), and null (N) types on MUC2, MUC5AC, MUC6, and CD10 immunostaining. Results The most common genomic alterations found in SBA tumors were TP53 (n = 16), followed by KRAS (n = 6), APC (n = 5), PIK3CA (n = 4), CTNNB1 (n = 3), KIT (n = 2), BRAF (n = 2), CDKN2A (n = 2), and PTEN (n = 2). Deficient MMR tumors were observed in 6 out of 22 patients. Tumor mucin phenotypes included 2 in G-type, 12 in I-type, 3 in GI-type, and 5 in N-type. APC and CTNNB1 mutations were not found in G-type and GI-type tumors. KRAS mutations were found in all tumor types except for G-type tumors. TP53 mutations were found in all tumor types. Although no single gene mutation was associated with overall survival (OS), we found that KRAS mutations were associated with significant worse OS in patients with proficient MMR tumors. Conclusions SBA genomic alterations in Japanese patients do not differ significantly from those reports in Western countries. Tumor localization, mucin phenotype, and MMR status all appear to impact SBA gene mutations.

Our previous study of duodenal adenoma using an endocytoscopy system (ECS) demonstrated that disappearance of goblet cells and spindle-shaped nuclei with loss of polarity were characteristic features. In addition, round duct openings and finger-like projections were observed in tubular adenoma and villous adenoma, respectively. Here, we retrospectively investigated six cases of histologically proven sporadic non-ampullary mucosal duodenal cancer (NAMDC) using ECS. Immunohistochemistry for CD10, MUC2, MUC5AC, and MUC6 was employed to determine the mucin phenotype in addition to conventional HE histology. Immunohistochemistry revealed one case involving the duodenal bulb that was considered to be the mixed type. The other five cases, located in the second or third portion, were considered to be the intestinal type. Vital staining of the mixed-type case was considered insufficient for ECS observation because of surface mucus. However, all five cases of intestinal-type duodenal cancer demonstrated a villous structure, disappearance of goblet cells and enlarged nuclei with loss of polarity. Tubular structures were admixed in four of those cases. Four cases demonstrated oval-shaped nuclei, and one case had spindle-shaped nuclei. Cases showing spindle-shaped nuclei in most of the lesion were diagnosed histologically as cancer in adenoma where the adenomatous component of the tumor was dominant. Oval-shaped nuclei and nuclear enlargement are the characteristic features of NAMDC revealed by ECS and are included among the histological criteria used for diagnosis. ECS offers the potential to perform real-time histological diagnosis of NAMDC in vivo.