Arginase-1 is frequently positive in hepatoid adenocarcinomas

Hepatoid adenocarcinoma is a rare extrahepatic tumor, which shows morphological and immunohistochemical similarities to hepatocellular carcinoma (HCC). Hence, hepatoid adenocarcinoma can cause diagnostic confusion with HCC. Arginase-1 immunostain has been recently shown to be an excellent marker of normal hepatocytes and is a sensitive and specific marker for HCC. However, the expression of Arginase-1 in hepatoid adenocarcinoma has not been...