Detection and endoscopic classification of intraductal neoplasms of the bile duct by peroral cholangioscopy with narrow-band imaging (with videos).

BACKGROUND AND AIMS: Indirect diagnostic modalities are unsatisfactory for detecting intraductal neoplasm of the bile duct (IN-B), which can be detected by peroral cholangioscopy (POC) with narrow-band imaging (NBI). We investigated the POC findings of IN-B and developed a feasible endoscopic classification system. METHODS: Four hundred seventy-one patients who underwent direct POC from April 2008 to July 2020 were enrolled. Intraductal superficial lesions of the bile duct (ISL-Bs) were classified according to surface structure and microvascular pattern on POC with NBI and correlated to histologic findings after POC-guided forceps biopsy sampling (POC-FB) or surgery. The primary outcome was the detection rate of IN-Bs, and the secondary outcomes were the associations of POC findings with IN-B, technical success rates of POC and POC-FB, and adverse events. RESULTS: Direct POC was successful in 458 of 471 patients (97.2%). Among the patients, 131 (27.8%) exhibited ISL-Bs. The technical success rate of POC-FB was 94.7% (124/131). Among the 124 patients who underwent POC-FB, IN-B was revealed in 54 (43.5%), for a detection rate of 11.8% (54/458). Papillary lesions (P = .041), nodular lesions (P = .044), and irregularly or regularly dilated and tortuous vessels (P = .004 and P = .006, respectively) were POC findings associated with IN-B. The area under the receiver-operating characteristic curve of the novel classification system was .899. CONCLUSIONS: POC with NBI can be useful for the detection of IN-Bs. Our novel classification system based on both surface structure and microvascular pattern may allow differentiation of IN-B from ISL-Bs.