Rare case of idiopathic sclerosing cholangitis, which was difficult to distinguish from cholangiocarcinoma: A case report.

It is often difficult to correctly diagnose patients who present with dilation of the bile duct. Cholangiocarcinoma, primary sclerosing cholangitis (PSC) and immunoglobulin (Ig)G4-related sclerosing cholangitis must be considered as potential diagnoses for these cases. The current study presents a 73-year-old female patient who presented with a high fever and abdominal pain. Contrast-enhanced computed tomography and magnetic resonance cholangiopancreatography revealed stenosis and dilation of the intrahepatic bile duct without solid components. It was suspected that the patient had intrahepatic cholangiocarcinoma. A left liver lobectomy, cholecystectomy and distal gastrectomy combined with a D2 lymph node dissection were performed. A pathological examination of the liver revealed increased fibrosis in the stroma, irregular bile duct dilation and clusters of inflamed lymph cells. No carcinoma or IgG4-positive plasma cells were observed and the typical findings of PSC were not detected. Based on these clinical and pathological results, the diagnosis was idiopathic sclerosing cholangitis, which is particularly rare. It is often difficult to preoperatively differentiate between cholangiocarcinoma and benign bile duct stenosis.