Abstract: Objective  To explore the clinical characteristics and improve the detection of early gastric cancer in  patients with autoimmune gastritis (AIG). Methods  A total 30 patients diagnosed with AIG who underwent endoscopic treatment for gastric early cancer at Beijing Friendship Hospital from 2018 to 2024 were enrolled retrospectively. The baseline characteristics, serological indicators, endoscopic and histopathological data of the patients were collected and analyzed. Further subgroup comparisons were conducted based on gender and Helicobacter pylori (Hp) infection status. Results  Among the 30 patients, 20 were female (66.7%), with a mean age of （64.93±7.68）years. Five patients (29.40%) were infected with Hp. The median values of pepsinogen Ⅰ (PG Ⅰ) and PG Ⅰ/Ⅱ ratio were 7.10 μg/L and 1.00, respectively, while the mean gastrin-17 (G17) level was （121.10 ± 120.15）pmol/L. The level of hemoglobin (Hb), free iron, ferritin, and vitamin B₁₂ were all within the normal range. There were 21 cases (70.00%) with lesions located in corpus，among which 16 cases (53.33%)  were type Ⅱa  lesions and 15 cases (50.00%)  were type Ⅰlesions. The predominant pathological type was tubular adenocarcinoma,with a total of  29 cases (96.67 %). Female patients exhibited significantly lower levels of Hb (P =0.012) and free iron (P <0.001) compared to male patients. Female also had lower vitamin B12 level ［ (161.25±76.49） pg/mL，P =0.012］, which was below the normal range and the difference was a statistically significant. No significant difference was observed between Hp-infected and non-infected patients. Conclusion  Among AIG patients with early gastric cancer, female, corpus elevated or flat lesion and tubular adenocarcinoma were predominated. For female AIG patients with vitamin B₁₂ deficiency, vigilance for the occurrence of gastric early cancer is warranted.

Key words: autoimmune gastritis, atrophic gastritis, gastritis, early gastric cancer, gastric adenocarcinoma, vitamin B₁₂