Pathomorphological and immunohistochemical studies were conducted on cases of hepatocellular carcinoma (HCC) with pale bodies (PB). HCC containing PBs was seen in 6 (5.7%) of 106 consecutively resected HCC cases. It was of interest that varying degrees of sclerotic change were found in 4 of the 6 cases and a certain correlation between PBs and sclerotic change of HCC tissue was suggested. Histologically, PBs were identified as a pale amorphous substance with a distinct margin and most of PBs occupied the entire cytoplasm of the cancer cells. PBs were practically negative for periodic-acid Schiff, and were also negative for phosphotungstic acid hematoxylin and orcein stains. Ultrastructurally, PBs were found to be a mass of granular or fibrillar materials having a single-layered limiting membrane, and dilated rough endoplasmic reticular (rER) were also found in the vicinity of PBs, suggesting the presence of a close relationship between rough endoplasmic reticula and PBs. Most PBs were found to be strongly positive for anti-fibrinogen antibody and some of them were weakly positive for anti-albumin, but were solely negative for other antibodies such as anti-HBs antigen, anti-alpha-1-antitrypsin, and anti-ferritin. According to those findings, PBs were thought to be fibrinogens accumulating in cystic rER due to a defective intracellular transport or an excretion disturbance.