Intraductal papillary neoplasm of the bile duct: diagnostic challenges in a tertiary center

Intraductal papillary neoplasm of the bile duct (IPNB) is an uncommon biliary tumor with recognized malignant potential and a broad clinicopathological spectrum. Its diagnosis remains challenging, particularly in extrahepatic disease, due to limitations of cross-sectional imaging. We report a consecutive series of five patients diagnosed with IPNB in a tertiary hepatobiliary center, highlighting their clinical, radiologic, endoscopic, and pathological features. Most patients presented with obstructive jaundice or cholangitis, and lesions were predominantly located in the distal bile duct. Cross-sectional imaging showed bile duct dilatation but often yielded inconclusive findings or underestimated intraductal disease, frequently leading to suspicion of cholangiocarcinoma or indeterminate strictures. Cholangioscopy provided additional diagnostic value by enabling direct visualization of characteristic villous or papillary lesions and facilitating targeted biopsies, contributing variably to diagnostic clarification. Histopathology demonstrated high-grade dysplasia in most cases, with one patient harboring invasive carcinoma. All patients required biliary drainage, and most underwent or were considered for surgical resection. These findings highlight the diagnostic discordance between preoperative assessment and definitive pathological diagnosis in IPNB and underscore the limitations of conventional imaging. Cholangioscopy represents a valuable complementary tool in the evaluation of indeterminate biliary strictures, although its findings should be interpreted within a multimodal diagnostic approach.