2012 Volume 54 Issue 7 Pages 2006-2013
A 39-year-old man was admitted to our hospital for further examination of an elevated gastric lesion that had been incidentally identified in an upper gastrointestinal series as part of a medical checkup. Endoscopy revealed a peculiar elevated lesion, in the form of a whitish, flat elevation with conspicuous reddish nodularity in part, measuring 30 mm in diameter, at the greater curvature of the lower body of the stomach. No association with background gastric mucosa of chronic gastritis or intestinal metaplasia with Helicobacter pylori was apparent clinically. Biopsy specimens taken from the lesion showed proliferated atypical gastric glands, but distinguishing between tubular adenoma and tubular adenocarcinoma was difficult. As a result, endoscopic submucosal dissection was performed with en bloc resection of the lesion. Histologically, most of the tumor in the resected specimen comprised proliferated gastric glands with low-grade atypia, with positive immunohistochemical staining for MUC5AC and M-GGMC-1. However, some cancerous lesions were seen limited to the mucosa of the tumor. Final diagnosis of the tumor was pType 0-I+IIa, well-differentiated tubular adenocarcinoma in tubular adenoma, gastric type, 30 × 25 mm, pT1a(M), UL(-), ly(-), v(-), HM0, VM0. Adenomas with a gastric phenotype are considered to show a higher risk of malignant transformation, but distinguishing between malignant and benign tumors form biopsy specimens is difficult. Active application of endoscopic submucosal dissection may thus facilitate correct diagnosis and treatment of such cases.
