Background/Aims: Cholecystitis can occur after the placement of covered self-expandable metallic stents for distal malignant biliary obstructions. We aimed to identify risk factors for cholecystitis following covered self-expandable metallic stent placement. Methods: We investigated risk factors related to cholecystitis following covered self-expandable metallic stent placement in 118 patients with distal malignant biliary obstructions between January 1, 2015 and April 30, 2019. Endoscopic assessments and tumor invasion to the arteries feeding the gallbladder were determined by a pancreaticobiliary endoscopist and a radiologist, respectively. Results: The median patient age was 72 years (men, 61.0%). The flow of the contrast agent into the gallbladder and tumor involvement in the orifice of the cystic duct were observed in 35 (29.7%) and 35 (29.7%) patients, respectively. During the observation period (median, 179 days), cholecystitis occurred in 18 (15.3%) patients. Multivariate analysis revealed the flow of the contrast agent into the gallbladder (p=0.023) and tumor involvement in the orifice of the cystic duct (p=0.005) as significant independent risk factors associated with cholecystitis. Conclusions The flow of the contrast agent into the gallbladder and tumor involvement in the orifice of the cystic duct are potential independent risk factors for cholecystitis following the placement of covered self-expandable metallic stents. A follow-up prospective study is warranted to validate their influence.

Background/Aims: Cholecystitis can occur after the placement of covered self-expandable metallic stents for distal malignant biliary obstructions. We aimed to identify risk factors for cholecystitis following covered self-expandable metallic stent placement. Methods: We investigated risk factors related to cholecystitis following covered self-expandable metallic stent placement in 118 patients with distal malignant biliary obstructions between January 1, 2015 and April 30, 2019. Endoscopic assessments and tumor invasion to the arteries feeding the gallbladder were determined by a pancreaticobiliary endoscopist and a radiologist, respectively. Results: The median patient age was 72 years (men, 61.0%). The flow of the contrast agent into the gallbladder and tumor involvement in the orifice of the cystic duct were observed in 35 (29.7%) and 35 (29.7%) patients, respectively. During the observation period (median, 179 days), cholecystitis occurred in 18 (15.3%) patients. Multivariate analysis revealed the flow of the contrast agent into the gallbladder (p=0.023) and tumor involvement in the orifice of the cystic duct (p=0.005) as significant independent risk factors associated with cholecystitis. Conclusions The flow of the contrast agent into the gallbladder and tumor involvement in the orifice of the cystic duct are potential independent risk factors for cholecystitis following the placement of covered self-expandable metallic stents. A follow-up prospective study is warranted to validate their influence.

Background/Aims: In stereomicroscopic sample isolation processing, the cutoff value (≥4 mm) of stereomicroscopically visible white cores indicates high diagnostic sensitivity. We aimed to evaluate endoscopic ultrasound-guided tissue acquisition (EUS-TA) using a simplified stereomicroscopic on-site evaluation of upper gastrointestinal subepithelial lesions (SELs). Methods: In this multicenter prospective trial, we performed EUS-TA using a 22-gauge Franseen needle in 34 participants with SELs derived from the upper gastrointestinal muscularis propria, requiring pathological diagnosis. The presence of stereomicroscopically visible white core (SVWC) in each specimen was assessed using stereomicroscopic on-site evaluation. The primary outcome was EUS-TA’s diagnostic sensitivity with stereomicroscopic on-site evaluation based on the SVWC cutoff value (≥4 mm) for malignant upper gastrointestinal SELs. Results: The total number of punctures was 68; 61 specimens (89.7%) contained stereomicroscopically visible white cores ≥4 mm in size. The final diagnoses were gastrointestinal stromal tumor, leiomyoma, and schwannoma in 76.5%, 14.7%, and 8.8% of the cases, respectively. The sensitivity of EUS-TA with stereomicroscopic on-site evaluation based on the SVWC cutoff value for malignant SELs was 100%. The per-lesion accuracy of histological diagnosis reached the highest level (100%) at the second puncture. Conclusions Stereomicroscopic on-site evaluation showed high diagnostic sensitivity and could be a new method for diagnosing upper gastrointestinal SELs using EUS-TA.