[Exploration of a new clinical classification of esophagogastric junction adenocarcinoma]

Objective: To explore a new classification method for adenocarcinoma of esophagogastric junction (AEG). Methods: This study consisted of an anatomical investigation and a retrospective case series. Twelve adult cadaveric specimens were included (8 males, 4 females), with a height of (166.9±11.7)cm (range:155 to 179 cm) and an age of (63.3±7.5) years (range: 56 to 72 years). Additionally, data from 20 patients who underwent radical three-incision total esophagectomy with proximal gastrectomy for middle/upper esophageal cancer at the Department of Gastrointestinal Surgery, Shanxi Provincial Cancer Hospital from March to June 2025 were analyzed (16 males, 4 females; aged (60.5±8.7) years(range: 50 to 71 years)). Pathological examination was performed on intact normal tissues from the esophagogastric junction. Results: Anatomical dissection revealed that the esophagogastric junction is a transitional structure with distinct anatomical landmarks and boundaries, enveloped by a unique sleeve-like membranous structure (Laimer's ligament), exhibiting specific histological features. Surgical specimens showed that the longitudinal veins of the lower esophagus branched gradually as they extended toward the stomach, forming a capillary network 1 to 2 cm above the dentate line before reconverging into thicker gastric mucosal veins approximately 1 cm below the dentate line. Histopathological examination further demonstrated that the transition from esophageal squamous epithelium to gastric columnar epithelium was not abrupt at the "Z-line" but exhibited overlapping, with gastric columnar epithelial cells migrating upward into the submucosa of the esophageal squamous epithelium for several millimeters. Based on anatomical findings and endoscopic landmarks, the Chinese classification of adenocarcinoma of esophagogastric junction (CHAEG) was proposed. Tumors were categorized into three types according to their origin: (1) CHAEG-E (perforator zone type): endoscopic tumor origin at the perforator zone; (2) CHAEG-P (palisade zone type): endoscopic tumor origin at the palisade zone; (3) CHAEG-G (gastric zone type): endoscopic tumor origin at the gastric zone. Each type was further subdivided into six subtypes based on the extent of tumor invasion at the upper and lower poles. Conclusions: This study preliminarily proposes a novel classification method for AEG, which may help resolve controversies regarding the extent of upper and distal resection margins and lymphadenectomy during radical surgery. However, the clinical value of this classification requires further investigation.