The best immunohistochemical panel for differentiating hepatocellular carcinoma from metastatic adenocarcinoma.

It can be difficult to differentiate hepatocellular carcinoma (HCC) from metastatic adenocarcinoma (MA). An appropriate immunohistochemical panel is required for the differential diagnosis. This study aimed at finding the best panel, including hepatocyte-specific antigen (Hepatocyte), pCEA, CD10, Villin, CD34, TTF-1, MOC-31, CK7, and CK20 antibodies. Sixty-eight cases of HCC and 107 cases of MA were investigated. Hepatocyte positivity was seen in 95.6% of HCCs and in 1.9% of MAs. pCEA was expressed in 47.8% of HCCs and in 86.8% of MAs. CD10 stained 73.13% of HCCs and 36.9% of MAs. Villin was positive in 23.5% of HCCs and in 81.0% of MAs. Canalicular staining with pCEA, CD10, and Villin was seen only in HCCs. Sinusoidal CD34 staining was seen only in 42.6% of HCCs. A small subset of HCCs demonstrated cytoplasmic TTF-1 and MOC-31. CK7 was expressed in 29.4% of HCCs and in 29.9% of MAs, whereas CK20 stained 14.7% of HCCs and 62.6% of MAs. In conclusion, Hepatocyte should be combined with pCEA, MOC-31, CD10, and CD34. Canalicular staining with pCEA, CD10, and Villin is specific for HCC. CK7 and CK20 expression may be seen in some HCCs. We suggest that the best panel for discriminating HCC from MA should contain Hepatocyte, MOC-31, pCEA, CD10, and CD34.