Intraductal Papillary Neoplasm With Associated Invasive Cholangiocarcinoma and Biliary Intraepithelial Neoplasia in Primary Sclerosing Cholangitis: A Case Report.

Intraductal papillary neoplasm of the bile duct (IPNB) is a biliary epithelial tumor that represents a recognized precursor lesion of cholangiocarcinoma. We report the case of a 60-year-old woman who presented to the emergency department with acute abdominal pain. A CT scan performed for suspected nephrolithiasis incidentally revealed an irregular hypodense lesion in segment VI of the liver with associated intrahepatic bile duct dilatation. Further evaluation with MRI and magnetic resonance cholangiopancreatography (MRCP) demonstrated a papillary intraductal mass within a dilated bile duct, appearing hyperintense on T2-weighted images and hypointense on T1-weighted images, and showing diffusion restriction and early contrast enhancement. Based on these findings, a preliminary diagnosis of IPNB was made, and the patient underwent right hepatic resection. Histopathological examination confirmed IPNB of mixed intestinal and pancreatobiliary type with high-grade dysplasia, associated with two foci of invasive cholangiocarcinoma. Additional findings included biliary intraepithelial neoplasia and primary sclerosing cholangitis with advanced fibrosis. This case highlights the importance of recognizing the imaging features of intraductal biliary tumors and demonstrates the value of MRI with MRCP in establishing the diagnosis. Early detection of IPNB is crucial, particularly in patients with underlying inflammatory biliary disease, as timely surgical treatment may prevent progression to advanced cholangiocarcinoma.