Hepatic hilar inflammatory pseudotumor mimicking cholangiocarcinoma with cholangitis and phlebitis--a variant of primary sclerosing cholangitis?

Inflammatory pseudotumor (IPT) of the liver is rare. We present a case of hepatic IPT mimicking cholangiocarcinoma in which the tumor was located at the left porta hepatis. The patient was a 64-year-old man in whom abnormal liver function test results had been noted incidentally during an annual health checkup in 1993: the patient declined to go to the hospital for further examination. At the annual health checkup the following year, abnormal liver function test results were noticed again, and this time he did go to a hospital, where a hepatic mass was found. Laboratory test results were unremarkable. Based on the location of the lesion and the findings of a variety of imaging modalities, such as ultrasound and computed tomography examination, the lesion was preoperatively diagnosed as hilar cholangiocarcinoma and was surgically resected. Pathologic examination of the resected lesion, however, revealed that it was not a true tumor but an inflammatory pseudotumor with marked destructive and sclerosing cholangitis mimicking primary sclerosing cholangitis (PSC) and obliterative phlebitis. Since the location and features of the tumor in the present case are very pertinent to the relationship between IPT and PSC, we describe its clinical and histologic features and discuss the findings in relation to PSC in the context of our literature review.