Helicobacter pylori (H pylori) eradication treatment can reduce the risk of gastric cancer. However, early gastric cancer (EGC) can still be detected after eradication. Meanwhile, EGC after eradication is challenging to diagnose by an endoscopist in some cases due to the lack of apparent characteristics and the complex mucosal status. This review aims to summarize the endoscopic and histological characteristics and the mucosal risk factors for gastric cancer after H pylori eradication. The literature was searched for possible reported gastric cancer after eradication in “PubMed.” These included related clinical studies and reviews, and unrelated or non-English articles were excluded. Endoscopically, EGC displays a small, reddish and depressed lesion, indistinct border, “gastritis-like” appearance and submucosal invasion. Histologically, it is divided into surface differentiation, nontumorous epithelium, and intestinal type. The risk factors include severe gastric atrophy, intestinal metaplasia in the corpus, and map-like redness. In conclusion, these studies on the characteristics and risk mucosal factors of patients with gastric cancer after H pylori eradication will drive the establishment of a novel endoscopic surveillance and diagnosis system for H pylori-eradicated patients.

BACKGROUND Colorectal mucosa-associated lymphoid tissue (MALT) lymphoma is a rare disease, and only a few cases have been reported to date. It has no specific clinical presentations and shows various endoscopic appearances. There is no uniform consensus on its treatment. With the advancement of endoscopic technology, endoscopic treatment has achieved better results in individual case reports of early-stage patients. CASE SUMMARY We report a case of rectal MALT in a 57-year-old Chinese man with no symptoms who received endoscopy as part of a routine physical examination, which incidentally found a 25 mm × 20 mm, laterally spreading tumor (LST)-like elevated lesion in the rectum. Therefore, he was referred to our hospital for further endoscopic treatment. Complete and curable removal of the tumor was performed by endoscopic submucosal dissection. We observed enlarged and dilated branch-like vessels similar to those of gastric MALT lymphoma on magnifying endoscopy with narrow-band imaging. And immunopathological staining showed hyperplastic capillaries in the mucosa. Histopathological findings revealed diffusely hyperplastic lymphoid tissue in the lamina propria, with a visible lymphoid follicle structure surrounded by a large number of diffusely infiltrated lymphoid cells that had a relatively simple morphology and clear cytoplasm. In addition, immunohistochemical analysis suggested strongly positive expression for CD20 and Bcl-2. Gene rearrangement results showed positivity for IGH-A, IGH-C, IGK-B, and IGL. Taking all the above findings together, we arrived at a diagnosis of extranodal marginal zone B-cell lymphoma of MALT lymphoma. Positron emission tomography-computed tomography examination showed no other lesions involved. The patient will be followed by periodic endoscopic observation. CONCLUSION In conclusion, we report a case of rectal MALT with an LST-like appearance treated by endoscopic submucosal dissection. Further studies will be needed to explore the clinical behavior, endoscopic appearance, and treatment of rectal MALT.