Diagnosis of Gastric Cancer by Magnifying Endoscopy with Narrow-Band Imaging: Impact and Clinical Feasibility of Narrow-Band Imaging for Accomplishing Endoscopic Pathology

Abstract

Although early and precise endoscopic diagnosis of gastric cancer is crucial for reducing its high mortality rates, the diagnosis is difficult because of the broad and heterogeneous appearances of neoplastic mucosa and inflamed gastric mucosa. Narrow-band imaging yields very clear endoscopic images of fine mucosal structures (FMS) and microvessels and has advanced magnifying endoscopic diagnosis into a new stage, endoscopic pathology. Significant microvascular findings related to superficial depressed gastric cancer (0IIc) are dilation, abrupt caliber alteration, and heterogeneity in shape and tortuousness, and those of FMS are complete or partial disappearance. The histopathology of gastric cancer is predictable according to microvascular patterns; fine network pattern and corkscrew pattern correspond to well- and poorly differentiated adenocarcinomas, respectively. Al though we have to fully utilize these endoscopic findings for accomplishing endoscopic pathology, the relative importance of the two microstructures differs according to the macroscopic appearance of gastric cancers. In superficial elevated gastric cancer (0IIa), FMS findings such as heterogeneity in shape have greater meaning than microvascular findings because of the frequent absence of irregular microvessels. In superficial flat gastric cancer (0IIb), irregular microvessels enclosed in a villous or papillary microstructure named intrastructural irregular vessel (ISIV) is specific, and the relative importance of FMS is lower.