Microvascular structural changes in esophageal squamous cell carcinoma pathology according to intrapapillary capillary loop types under magnifying endoscopy.

Background: The intrapapillary capillary loop (IPCL) characteristics, visualized using magnifying endoscopy, are commonly assessed for preoperative evaluation of the infiltration depth of esophageal squamous cell carcinoma (ESCC). Japan Esophageal Society (JES) classification is the most widely used classification. Microvascular structural changes are evaluated by magnifying endoscopy for the presence or absence of each morphological factor: tortuosity, dilatation, irregular caliber, and different shapes. However, the pathological characteristics of IPCLs have not been thoroughly investigated, especially the microvascular structures corresponding to the deepest parts of the lesions' infiltration.

Aim: To investigate differences in pathological microvascular structures of ESCC, which correspond to the deepest parts of the lesions' infiltration.

Methods: Patients with ESCC and precancerous lesions diagnosed at Peking University Third Hospital were enrolled between January 2019 and April 2023. Patients first underwent magnified endoscopic examination, followed by endoscopic submucosal dissection or surgical treatment. Pathological images were scanned using a three-dimensional slice scanner, and the pathological structural differences in different types, according to the JES classification, were analyzed using nonparametric tests and t-tests.

Results: The 35 lesions were divided into four groups according to the JES classification: A, B1, B2, and B3. Statistical analyses revealed significant differences (^a P < 0.05) in the short and long calibers, area, location, and density between types A and B. Notably, there were no significant differences in these parameters between types B1 and B2 and between types B2 and B3 (P > 0.05). However, significant differences in the short calibers, long calibers, and area of IPCL were observed between types B1 and B3 (^a P < 0.05); no significant differences were found in the density or location (P > 0.05).

Conclusion: Pathological structures of IPCLs in the deepest infiltrating regions differ among various IPCL types classified by the JES classification under magnifying endoscopy, especially between the types A and B.