Hyaline globules and intracellular lumina in a hepatocellular carcinoma

The authors report ultrastructural findings on the morphogenesis of hyaline globular inclusions (HG) of a moderately well-differentiated hepatocellular carcinoma, with the features of a fibrolamellar variant. Pale blue cytoplasmic inclusions (pale bodies) of the tumor cells were shown to be intracellular lumina lined with numerous microvilli. Our findings suggest that HG were formed apparently by the successive deposition of fine granular materials in the lumina. Small accumulations were present in the intracellular lumina, which were seen on light microscopy as central hyaline cores of pale inclusions. Larger globular deposits, corresponding to HG and presumably mature ones, were lined closely with membranes devoid of microvilli that were probably shed intraluminally. Our observation was discussed with relation to the previous findings on the inclusions.