Intraductal papillary neoplasm of the bile duct found incidentally during examination of colonic disease: A case report

Background: Intraductal papillary neoplasm of the bile duct (IPNB) is a relatively rare bile duct neoplasm in the multistep carcinogenesis pathway towards cholangiocarcinoma. The diagnosis of IPNB is challenging, and its malignant potential means that its prognosis is related to the performance of R0 resection. We experienced a patient with IPNB detected during close examination of colonic disease and subsequently treated surgically. Case presentation: A 54-year-old man presented to an outside hospital with abdominal pain. Enhanced computed tomography showed wall thickening in the ascending colon and a cystic lesion close to the posterior segmental branch of the bile duct in the liver. Colonoscopy showed diverticulitis and severe stenosis in the ascending colon, with no finding of malignancy. Differential diagnosis of the liver tumor was IPNB, mucinous cystic neoplasm, or metastatic tumor from the colonic disease. The patient underwent hepatectomy and simultaneous right hemicolectomy for severe diverticulitis. Histopathological examination of the liver revealed IPNB with an associated invasive carcinoma. Conclusions: We report a relatively rare case of IPNB. Although preoperative diagnosis of IPNB remains challenging, complete resection is important for a favorable prognosis. Correspondence to: Akio Saiura, Department of Gastroenterological Surgery, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, 3-831 Ariake, Koto-ku, Tokyo 135-8550, Japan, E-mail: [email protected]