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

• Research Background

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. In 2007, Tsukamoto et al. reported the first case of gastric adenocarcinoma with chief cell differentiation. In 2010, Ueyama et al. proposed gastric adenocarcinoma of fundic-gland type (GA-FG) as a novel variant of gastric adenocarcinoma. Subsequently, gastric adenocarcinoma of fundic-gland mucosa type (GA-FGM) was also reported; this subtype exhibits gastric foveolar epithelial differentiation in addition to fundic gland differentiation and demonstrates more aggressive behavior.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:

• Oxyntic gland adenoma (OGA);
• Gastric adenocarcinoma of fundic-gland type (GA-FG);
• 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. Furthermore, the majority of reported cases have been described by Japanese researchers, and data on the incidence, detection rate, treatment strategies, and clinical prognosis of GEN-FGML in other countries remain scarce.

Based on this, there is an urgent need for systematic research into the clinicopathological characteristics, endoscopic features, treatment strategies, and prognosis of GEN-FGML. This study aims to provide high-quality, evidence-based medical evidence to inform the development of standardized treatment strategies, curative evaluation, and prognostic assessment for GEN-FGML. Specifically, 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.

• Research Objectives

The objectives of this study are to:

• Retrospectively collect cases and clinical data related to GEN-FGML from multiple centers across China.
• Compare the clinicopathological characteristics, endoscopic features, molecular biological characteristics, clinical treatment modalities, and patient prognosis among the different subtypes of GEN-FGML.
• Provide high-quality, evidence-based data to support the development of standardized treatment strategies, curative resection evaluation, and prognostic assessment for GEN-FGML.

Inclusion criteria

• Patients who voluntarily provided written informed consent between August 1, 2010 and August 1, 2024
• Age ≥18 years at diagnosis
• Confirmed diagnosis of GEN-FGML

Exclusion criteria

• The clinicopathological data of the lesion(s) were missing