OBJECTIVE: This study aims to elucidate the relationship between gastric mucosal atrophy, cystic dilatation, and their associated histopathological characteristics. METHODS: A comprehensive analysis was conducted on endoscopic biopsy specimens from 527 cases exhibiting gastric mucosal cystic dilatation. Detailed histological observations and immunohistochemical analysis were performed. RESULTS: This study included 527 endoscopic biopsy and ESD samples, with a male predominance of 313 cases (59.4%) and 214 female cases (40.6%). The age distribution was as follows: 207 cases (39.3%) were ≤ 60 years, while 320 cases (60.7%) were >
60 years. Regarding cystic dilatation types, 287 cases (54.5%) were identified as simple cystic dilatation, and 240 cases (45.5%) were classified as compound cystic dilatation. Gastric mucosal atrophy was observed in all cases of cystic dilatation, with the atrophic process initially disrupting the structural integrity of the gastric glands. This led to increased interstitial tissue and widening of glandular septa, followed by compensatory hyperplasia and cystic cavity formation. Simple cystic dilatation (54.5%) and compound cystic dilatation (45.5%) were distinguished based on the extent of cellular and structural changes. Simple cystic dilatation could progress to early gastric cancer, presenting as gastric papillary cystadenocarcinoma, while compound cystic dilatation could lead to tubular papillary adenocarcinoma. The progression from simple to complex lesions involved low- and high-grade intraepithelial neoplasia, ultimately resulting in mixed cystadenocarcinoma-glandular tube papillary carcinoma, indicative of early-stage gastric cancer. CONCLUSION: The classification, grading, and histopathological characteristics of cystic dilatation in the gastric mucosa are crucial for guiding clinicians in precise treatment and vigilant monitoring of malignant transformation. This approach is significant for the prevention and control of gastric cancer progression.