Departments of *Pathology and Cell Biology †Medicine, Division of Digestive and Liver Diseases, Columbia University College of Physicians and Surgeons, New York, NY ‡Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.
The histopathologic distinction between posttransplantation fibrosing cholestatic hepatitis C (FCH-C) and biliary obstruction (BO) is challenging. We sought to identify histopathologic features that could be useful in the differential diagnosis between these 2 entities. A total of 38 cases of hepatitis C virus (HCV)-negative, cholangiography-proven BO (including 16 posttransplant and 22 nontransplant patients) and 13 patients with posttransplantation FCH-C were included. FCH-C patients were characterized by cholestatic disease, high HCV viral load, no evidence of biliary tract obstruction on imaging, and typical histopathologic findings (≥3 of the following: 1, prominent ductular reaction; 2, hepatocyte swelling with lobular disarray; 3, periportal sinusoidal fibrosis, and 4, cholestasis). Biopsies were evaluated with hematoxylin and eosin, Masson trichrome, Victoria blue, and rhodanine stains. Cytokeratin 7 (CK7) immunohistochemistry was used to assess for the presence of CK7+ intermediate hepatobiliary cells. We found that portal edema (63.1% vs. 7.6%; P<0.0001), bile duct dilatation (26.3% vs. 0%; P=0.0003), acute cholangitis (15.7% vs. 0%; P=0.008), bile infarcts (10.5% vs. 0%; P=0.03), periductal fibrosis (23.6% vs. 0%; P=0.0007), and periportal copper deposition (60.5% vs. 15.3%; P=0.0006) are significantly more common in BO, whereas hepatocellular swelling with lobular disarray (84.6% vs. 5.2%; P<0.0001) and periportal sinusoidal fibrosis (34.2% vs. 100%; P<0.0001) are seen more frequently in FCH-C. Furthermore, marked ductular reaction with rare or absent CK7+ intermediate cells is highly suggestive of FCH-C in this context (73.6% vs. 7.6%; P<0.0001). In summary, this study offers a comprehensive characterization of the histologic features discriminating FCH-C from BO.