BACKGROUND There is often a discrepancy between results from endoscopic forceps biopsy and resected specimen. We aimed to identify endoscopic predictors for undifferentiated histology in differentiated gastric neoplasms prior to endoscopic resection.

METHODS Medical records of the patients who underwent endoscopic submucosal dissection (ESD) for biopsy-proven differentiated gastric neoplasms at Seoul National University Hospital between July 2005 and July 2014 were retrospectively reviewed. The lesions were divided into two groups based on the final histologic result of ESD: differentiated adenocarcinoma (DA group) and undifferentiated histology (UDH group). The discordant rate, clinicopathologic characteristics, and endoscopic factors were analyzed.

RESULTS A total of 1641 early gastric cancers from 1615 patients were included. Of these, 1556 (94.8%) were diagnosed as DA and 85 (5.2%) as UDH. The mean age was significantly lower, and number of women was higher in the UDH group than in the DA group. On multivariate analysis, age <65 years [odds ratio (OR) 1.75, 95 % confidence interval (CI) 1.10-2.80], female sex (OR 3.19, 95% CI 2.00-5.08), endoscopic size >10 mm (OR 1.81, 95% CI 1.12-2.92), depressed type (OR 2.85, 95% CI 1.56-5.21), nodularity (OR 2.83, 95% CI 1.59-5.05), and whitish discoloration (OR 19.64, 95% CI 6.98-55.25) were independent predictors.

CONCLUSIONS Female sex, age <65 years, large endoscopic size, depressed morphology, surface nodularity, and whitish discoloration were predictors for UDH. Meticulous attention should be paid to the lesions with these endoscopic predictors for determining the risk of UDH prior to endoscopic resection.