LAUSR

AN 84-YEAR-OLD WOMAN presented to our hospital and had an incidental finding of a gallbladder tumor on computed tomography (CT). CT revealed a contrastenhanced tumor with partial calcification measuring 33 mm in the neck of the gallbladder (Fig. 1). Endoscopic ultrasound (EUS) showed a papillary tumor with partial calcification, and EUS imaging with contrast revealed hypervascularity within the tumor. Based on these imaging findings, a malignant gallbladder tumor was suspected. We performed endoscopic retrograde cholangiography (ERCP) using a duodenoscope (TJF260V; Olympus, Tokyo, Japan). ERCP revealed a filling defect in the gallbladder. Subsequent cholangioscopy with SpyGlass DS (Boston Scientific, Natick, MA, USA) revealed no abnormalities in the common bile duct or the confluence of the cystic ducts. The cystic duct was mildly dilated (12 mm in diameter), and guidewire insertion into the gallbladder, followed by successful insertion of the SpyGlass DS into the gallbladder, was performed (Video S1). A papillary tumor was found, which was mainly located on the gallbladder neck and partially extended to the cystic duct (Fig. 2). Based on these findings, intracholecystic papillary neoplasm (ICPN) was suspected. Forceps biopsy using a SpyBite (Boston Scientific) revealed that the pathology included a papillary structure that consisted of a low-grade epithelium and a slight disorder in the nuclear arrangement. The diagnosis was ICPN-derived carcinogenesis. The same findings were confirmed in postoperative pathology. To the best of our knowledge, this is the first case in which ICPN was diagnosed preoperatively under direct vision. Reports of cholangioscopy insertion into the gallbladder are rare, with only a few cases of gallbladder carcinoma. According to these reports, a dilated and straightened cystic duct is critical to the procedure’s success. If the cystic duct is dilated and