Electron microscopic observations on the cholesterol distributed in the epithelial cells of the gallbladder.

Epithelial cells of eight human gallbladders with cholesterosis were examined. In the supranuclear portion of the epithelial cells of one case, many spicular, circular and plate-like crystalline structures are present. Spicular and circular structures have not a limiting membrane, but plate-like structures are apparently bounded by a limiting membrane that clearly shows trilamellar structure. After digitonin treatment, the spicular and circular crystalline structures become denser. On the other hand, the plate-like structures do not become denser by digitonization. In the epithelial cells that contain no crystalline structure, there also occur many reaction precipitates after digitonization. These findings may suggest that free cholesterol is highly present in the epithelial cells of gallbladder with cholesterosis and that it, in some case, precipitates in the form of spicular or circular structure for the rapid fixation process.