A histopathological analysis of five cases of adenomatous hyperplasia containing minute hepatocellular carcinoma

We present five cases of adenomatous hyperplasia (AH) containing minute hepatocellular carcinoma (HCC) in cirrhotic liver. All the patients were Japanese, four males and one female, ranging in age from 60 to 80 years. Two of the specimens were obtained at surgery and the others at autopsy. The AH specimens ranged from 2.0 to 3.0 cm in diameter, and the maximum diameter of HCC foci in the AH was 2.0 cm. Histologically, apart from the HCC foci, the AH specimens showed intrinsic atypia, suggesting preneoplastic change. These features included an increase of both cellularity and the nucleo-cytoplasmic ratio, distortion of cord structure and pseudoacinar formation. All of the AH specimens contained typical portal triads. Details of diagnostic imaging were also obtained in four cases. The findings of the present study support the possibility that AH with intrinsic atypia is a preneoplastic lesion of HCC. The sequence of "adenomatous hyperplasia with intrinsic atypia-HCC foci" would thus represent part of the early phase of hepatocarcinogenesis in humans.