Post-endoscopic submucosal dissection bleeding (PEB) is one of the important complications after endoscopic submucosal dissection (ESD), but still difficult to predict. The present study aimed to identify significant risk factors for PEB according to onset time. Between November 2008 and January 2016, a total of 1864 lesions resected via ESD were analyzed. PEB was classified as either early or late according to onset time (within or after 24 hours post-ESD, respectively). During second-look endoscopy, the artificial ulcer bed was subjected to Forrest classification. A high risk of stigma was defined as active spurting bleeding, oozing bleeding, and a non-bleeding visible vessel in the ulcer. The endoscopic factors and medications associated with PEB were analyzed. PEB occurred in 77 lesions (4.1%): early only in 46 (2.4%), late only in 22 (1.1%), and early and late in 9 (0.4%). Among 55 early PEB events, 25 were asymptomatic and diagnosed during second-look endoscopy. Age ≤65 years, resection size ≥30 mm, procedure time ≥20 min, lower third of the stomach, erosion, and clopidogrel use were significantly associated with early PEB. If the number of risk factors were ≤1, the risk of early PEB was 0.6%. For late PEB, the mid to upper third of the stomach, undifferentiated carcinoma, erosion, high risk of stigma during second-look endoscopy, history of early PEB, and clopidogrel use were significant risk factors. If risk factors were absent, the risk of late PEB was 0.1%. For patients at high risk of early PEB, selective second-look endoscopy might be a useful. For patients at high risk of late PEB, careful monitoring of bleeding should be considered.

Incidental gastric subepithelial tumor (SET) is frequently found during endoscopy. Although endoscopic ultrasonography (EUS) can provide useful information, its diagnostic accuracy varies. Most of the potentially malignant tumors observed on EUS are hypoechoic lesions. Therefore, we aimed to investigate the diagnostic accuracy of EUS for hypoechoic lesions located in the submucosa or proper muscle layer. We also evaluated various characteristics for potential associations with diagnostic accuracy. A retrospective review was conducted of the medical records of 99 patients who were diagnosed with gastric SET and who underwent EUS with pathologic confirmation between March 2008 and April 2015. After reviewing the endoscopic and pathologic findings, we attempted to analyze factors that were associated with the diagnostic accuracy of EUS. The mean ± standard deviation size of the lesions was 20.0 ± 12.7 mm. The most common location was the upper third of the stomach (43.4%). The overall accuracy of EUS was 66.7%. No statistically significant difference in EUS accuracy was observed according to the location, size, or layer of the lesion. The following pathologic diagnostic methods were used: EUS-guided fine needle aspiration (3.0%), forceps biopsy (16.2%), deep tissue biopsy using cap-assisted mucosal resection (8.1%), endoscopic submucosal dissection (25.2%), and operation (47.5%). The accuracy of EUS according to the expected diagnosis of the lesion was 77.1% for gastrointestinal stromal tumor, 50% for neuroendocrine tumor, and 50% for ectopic pancreas. Although EUS is a useful tool for gastric SET in clinical practice, the accuracy of diagnostic EUS is suboptimal. When considering whether to treat gastric SET, the decision should be made based on the pathologic diagnosis.