Diffuse cirrhosis-like hepatocellular carcinoma: a clinically and radiographically undetected variant mimicking cirrhosis.

A rare variant of hepatocellular carcinoma (HCC) is encountered that produces small cirrhosis-like nodules diffusely throughout the liver (CL-HCC), instead of a larger evident mass. This pattern remains undetected as carcinoma clinically and radiographically and is unexpectedly discovered after liver transplantation in the explanted native liver. We studied 10 such cases (9 males and 1 female, age 35 to 80 y) from 4 medical centers. The pretransplant clinical, laboratory, and radiographical studies were reviewed to determine the cause and stage of liver disease, alpha-fetoprotein (AFP) levels, and detectability of a mass on imaging. All 10 cases had underlying cirrhosis of varying etiology [3 hepatitis C virus (HCV), 3 alcoholic hepatitis, 1 hepatitis B virus, 1 autoimmune, and 2 mixed HCV/alcoholic hepatitis and hemochromatosis/HCV] and underwent orthotopic liver transplantation with no preoperative clinical suspicion of HCC. Ultrasound and/or dynamic imaging showed cirrhosis and no definite HCC. AFP levels were only mildly elevated in only 3 of 10 cases (144, 150, and 252 ng/mL). Grossly, there were innumerable (from about 20 to >1000) small CL-HCC nodules (0.2 to 0.6 cm) scattered among cirrhotic nodules. Histologically, these were well or moderately differentiated HCC, often with pseudoglandular pattern, perinodular sclerotic rims, cholestasis, frequent Mallory bodies, and small vessel invasion. In addition to the usual HCC immunophenotype, CL-HCC showed frequent ubiquitin and cytoplasmic and membranous CD10 positivity, relatively low Ki-67 proliferative index and absence of AFP immunohistochemically. CL-HCC warrants recognition as a unique HCC variant that evades pretransplant detection despite massive tumor burden, mimics cirrhotic nodules, and shows some uncommon pathologic and immunophenotypical characteristics.