Hepatic inflammatory pseudotumor associated with chronic cholangitis: report of three cases.

We present three cases of hepatic inflammatory pseudotumor associated with chronic cholangitis. In these three cases the inflammatory pseudotumor was solitary, was present in the hepatic hilar region, and had been misdiagnosed as cholangiocarcinoma by imaging modalities and/or gross pathologic examination. Hilar bile ducts were embedded within the tumor. Histologically, these "tumors" consisted of an 2ad-mixed proliferation of lymphocytes, plasma cells, and fibroblasts with variable hyaline fibrosis. The phenotypes of lymphocytes and plasma cells within the tumor were immunohistochemically heterogeneous. Bile ducts and peribiliary glands embedded within these tumors showed nonspecific fibrosis and inflammation, and inflammatory changes of the bile ducts were imperceptibly merged with those of the inflammatory tumor, raising the possibility that these tumors may have arisen in relation to cholangitis. The bile ducts adjacent to the tumor also showed similar but milder nonspecific inflammatory changes. The pathogenesis of cholangitis was unknown in two cases and was speculated to be due to fungal infection in the remaining case. These cases may indicate that biliary tract disease(s) should be explored as the etiology of hepatic inflammatory pseudotumor.