Clinicopathological Features and Treatment Strategies for Gastric Epithelial Neoplasm of Fundic-gland Mucosa Lineage

Gastric epithelial neoplasm of fundic-gland mucosa lineage (GEN-FGML) is a rare pathological type of gastric cancer characterized by unique endoscopic features, including specific morphology, color, and changes in the surface and vascular patterns of the lesion. Histologically, GEN-FGML is an epithelial neoplasm exhibiting gastric fundic gland differentiation. Based on cellular differentiation and submucosal invasion, it can be classified into three subtypes: 1. Oxyntic gland adenoma (OGA); 2. Gastric adenocarcinoma of fundic-gland type (GA-FG); 3. Gastric adenocarcinoma of fundic-gland mucosa type (GA-FGM). GA-FGM can be further subdivided into three subtypes: Type 1 (regular exposed pattern), Type 2 (disordered exposed pattern), and Type 3 (disordered non-exposed pattern). Some studies have analyzed the clinicopathological characteristics, endoscopic features, molecular biological characteristics, treatment strategies, and prognosis of the different GEN-FGML subtypes. Generally, OGA and GA-FG present as low-grade epithelial neoplasms with a favorable prognosis, whereas GA-FGM exhibits higher rates of lymphovascular invasion and behaves as a high-grade malignant tumor.However, due to the currently limited number of reported cases, there are no international guidelines or consensus regarding the selection of treatment strategies for GEN-FGML, curative resection evaluation, and prognosis. In this study, the investigators aim to retrospectively collect data on GEN-FGML cases from multiple centers in China and compare the clinicopathological characteristics, molecular biological features, endoscopic characteristics, treatment strategies, and patient prognosis among the different GEN-FGML subtypes.