Pathomorphologic characteristics of 102 cases of thorotrast-related hepatocellular carcinoma, cholangiocarcinoma, and hepatic angiosarcoma.

The pathomorphologic characteristics of 102 autopsy cases of Thorotrast (Th)-related hepatic malignancies were described and compared to the features of non-Th-related cases. Among the 102 Th-related hepatic malignancies, 44 (43.1%) were cholangiocarcinoma (CHC), 39 (38.3%) were angiosarcoma (AGS), 16 (15.7%) were hepatocellular carcinoma (HCC), and 3 (2.9%) were double cancer. In the non-Th-related cases approximately 90% were HCC, and AGS was very rare. Grossly, the majority (91.7%) of Th-related CHC was located in the middle-peripheral portion of the liver. In contrast, 77.8% of the non-Th-related cases were located in the hilar portion. Th-related AGS was classified into four types: diffuse micronodular, multi-nodular, massive, and mixed multi-nodular and massive. Histologically, AGS was characterized by two cell types (spindle-shaped cells and polyhedral cells) and three growth patterns (sinusoidal, cavernous, and solid). In noncancerous areas foci of varying degrees of sinusoidal dilatation with hyperplastic changes of sinusoidal lining cells were observed in all AGS cases and in some of the cases of Th-related CHC and HCC cases. In many (80%) of the non-Th-related HCC, mixed macronodular and micronodular cirrhosis was associated. By contrast, in Th-related HCC cases cirrhosis was superimposed on varying degrees of hepatic fibrosis related to Th deposition in only four cases (21.1%). Taken together, these findings suggest that Th influences are more carcinogenic to epithelial cells of the bile duct and sinusoidal lining cells than hepatocytes.