Inflammatory pseudotumor of the liver with primary sclerosing cholangitis.

Inflammatory pseudotumor (IPT) of the liver is a rare benign variant of hepatic masses, and its exact etiology has not been elucidated. We report a case of IPT associated with primary sclerosing cholangitis (PSC). The patient was a 50-year-old man admitted to our hospital because of jaundice. Abdominal ultrasonography (US) and computed tomography showed multiple dilations of the intrahepatic bile ducts and multiple masses in the liver. On magnetic resonance imaging, the masses were slightly hypointense on T1-weighted images and slightly hyperintense on T2-weighted images. On T1-weighted images after the bolus infusion of Gd chelate, the masses had no contrast enhancement, and they were hypointense in the arterial phase and portal venous phase. However, they were slightly enhanced and became almost isointense relative to the surrounding normal liver parenchyma in the delayed phase. Endoscopic retrograde cholangiography demonstrated multiple irregular strictures and dilations of the intrahepatic bile ducts. Angiography demonstrated no abnormal findings, but, interestingly, subsequent dynamic CO2-enhanced US showed a strongly hyperechoic string, indicating that an artery had penetrated through the hypoechoic mass. A US-guided percutaneous needle biopsy revealed that the lesions were morphologically comparable to IPT. After cholangiography and microscopic analysis of the tumor, the final diagnosis was determined to be IPT of the liver with PSC. A number of previous reports have suggested a possible relationship between IPT and PSC, based on pathological findings. This report confirmed, based on clinical findings, that PSC is one of the causes of hepatic IPT.