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Background/Aims: To evaluate gastric early differentiate-type carcinogenesis, we attempted to identify clinicopathological and biological differences in differentiated-type minute intramucosal neoplasia (MIMN), which was defined as a tumor with a diameter of < 5 mm. Methods: We examined clinicopathological findings and biological factors, including TP53 overexpression, mucin phenotype, Ki-67-positive rate, MLH1, intranuclear accumulation of β-catenin, and DNA methylation status (low methylation epigenotype [LME], intermediate methylation epigenotype, and high methylation epigenotype [HME]) in MIMNs. In addition, non-MIMNs were also analyzed. In the present study, MIMN and non-MIMN were also examined based on low-grade dysplasia, high-grade dysplasia, and intramucosal cancer (IMC). Results: In clinicopathological findings, there were significant differences in sex ratios and tumor locations between MIMNs and non-MIMNs. Among the examined biological factors, no significant differences in the frequencies of biological factors were observed between the 2 intramucosal neoplasia types. However, the frequency of intranuclear accumulation of β-catenin was higher in non-MIMNs than in MIMNs. Finally, although the frequency of HME was significantly lower in MIMNs than in non-MIMNs, the opposite was observed for LME. Conclusions: The current finding suggested that DNA methylation and accumulation of β-catenin were closely associated with tumor development from MIMN to non-MIMN. [ABSTRACT FROM AUTHOR]

Background and Aims: We aimed to investigate an association between clinicopathological features, including immunohistochemical mucin phenotypes, and magnifying chromoendoscopic findings with crystal violet staining (ME-CV) in non-ampullary duodenal epithelial tumors (NADETs). Methods: A total of 55 patients with NADET were divided into 3 groups by mucin phenotype: intestinal, gastrointestinal, or gastric. ME-CV findings were classified into 4 patterns: convoluted, leaf-like, reticular/sulciolar, and pinecone. The clinicopathological features and ME-CV findings were compared among the mucin phenotypes. Results: Tumors of the gastric type were located in the duodenal bulb (p < 0.001), and contained pyloric gland adenoma (p < 0.001) more frequently than the other types. White-light endoscopy indicated that milk-white mucosa was less frequent in tumors of the gastric type than in those of the gastrointestinal type (p = 0.006) and the intestinal type (p < 0.001). ME-CV findings were significantly different between the gastric type and the other type (p = 0.028). Totally, 5 of 8 tumors of the gastric type manifested a pinecone pattern, 4 of which were compatible with pyloric gland adenoma. Conclusions: The endoscopic findings of NADETs differ according to mucin phenotype. A pinecone pattern under ME-CV may be characteristic of NADETs of the gastric type, especially pyloric gland adenoma. [ABSTRACT FROM AUTHOR]