Aim. To reveal and study basic endoscopic differential-significant criteria characterizing gastric-like form of primary non-Hodgkin's lymphoma (NHL) from adenocarcinoma and signet-ring cell carcinoma (SRCC) of the stomach.
 Materials and methods. In the prospective study, based of Blokhin National Medical Research Center of Oncology in the period from 2019 to June 2023, 106 patients with gastritic-like forms of primary NHL, adenocarcinoma and SRCC of the stomach were analyzed. Complex endoscopic study included examination in the modes of white light, magnification, narrow-band imaging (NBI, BLI, LCI) was done.
 Results. All patients were divided into three groups: MALT gastric lymphoma (38 patients, 35.8%), gastric adenocarcinoma (33 patients, 31.1%), and SRCC (35 patients, 33.1%). At MALT-lymphoma the tumor was localized in the antrum of the stomach (52.6%),adenocarcinoma and SRCC – in the body (45.5 and 60%). In the tumor structure in MALT-lymphoma of the stomach in 100% of cases multiple point areas of microdepressions and multicenter character of the lesion were determined. At adenocarcinoma – depressed area in the central part of tumor (45.5%), at SRCC – extended areas of microdepressions (51.4%) and multicentric character of lesions. At MALT-lymphoma the pit pattern in 63.2% is of "balloon" type, vascular – of tree-like type (84.2%). In adenocarcinoma the vascular pattern was of the loop-type (42.4%), in SRCC – of the corkscrew-type (74.3%). Demarcation line was observed only in adenocarcinoma (100%). At endosonographic study at MALT-lymphoma the tumor was coming from deep layers of mucous coat (100%), changes of regional lymph nodes (LN) were absent, at adenocarcinoma – from mucous membrane (100%), LN were not changed, at SRCC – submucous spread of tumor (100%), changes in LN (40%).
 Conclusion. Complex endoscopic examination is necessary to improve the quality of endoscopic examination of malignant gastric-like tumors, to determine the depth of invasion and spread of the tumor process, to assess the regional lymph drainage.