New subtype of gastric adenocarcinoma: mixed fundic and pyloric mucosa-type adenocarcinoma

A 73-year-old woman underwent upper endoscopic screening that revealed a 30-mm superficial elevated lesion in the anterior wall of the upper gastric body. The lesion had a whitish color and coarse granular surface in conventional white light endoscopy. Magnifying narrow-band imaging indicated irregular microvascular and microsurface patterns within a demarcation line. The microvessels had a distorted polygonal shape within the area surrounded by the marginal crypt epithelium. The patient underwent endoscopic resection. Histological examination of the resected specimen showed a very well- to well-differentiated tubular adenocarcinoma with differentiation toward the mixed fundic and pyloric mucosa, without chief cells. The histological and serological findings indicated the absence of Helicobacter pylori infection. The present case demonstrates a new histological subtype of gastric adenocarcinoma, which has characteristic endoscopic findings.