The connective tissue content of four different human liver tumors (Fibrolamellar carcinoma, FLC; hepatocellular carcinoma, HCC; focal nodular hyperplasia, FNH and hepatocellular adenoma, HCA) was investigated by computer aided morphometry. A significantly higher connective tissue content was found in FNH and FLC as compared to HCA and HCC. The distribution of the connective tissue was homogeneous in the cases of FNH, HCA and HCC, while a highly unhomogeneous distribution was observed in FLC cases.