Superficial spreading type of early gastric cancer with diagnostic difficulty and positive surgical margin: a case report.

An 83-year-old man visited our hospital because of difficulty swallowing. Gastroscopy revealed multiple ulcers and a reddish depression in the lesser curvature of the middle stomach. The initial biopsy showed regenerative atypia, so a gastroscopy was repeated every 3 months thereafter because of suspected malignancy. A biopsy performed 12 months after the initial gastroscopy revealed a well-differentiated adenocarcinoma. After determination of the planned oral resection line by two negative biopsies, laparoscopic distal gastrectomy was performed. The resected specimen showed a 0 - IIa + IIc lesion composed of well-to-moderately differentiated tubular adenocarcinoma, including hand-shaking-type gastric cancer. The oral resection margin was positive due to widespread mucosal extension; therefore, an additional total gastrectomy was needed. Cases of well-differentiated adenocarcinoma and its superficial extension may be difficult to diagnose via endoscopy and biopsy.