Bile canaliculi-like lumina in fibrolamellar carcinoma of the liver: A light- and electron-microscopic study and three-dimensional examination of serial sections

Flbrolamellar carclnoma (FLC) Is a varlant of hepatocellular carclnoma characterlzed by dlstlnct pathologlcel features. The presence of lntracellular lumlna resembling blle canallcull was previously reported in tumor cells of FLC on electron microscopy. Using light microscopy, we describe the presence of intracellular lumina In FLC, which was resected from a 15-year-old Japanese girl, as round structures llned wlth a brush-like border. These lumlna occasionally contained blle. Llght mlcroscopic examination of 1 pm thick serial sectlons of Eponembedded tissue samples showed that the lumlna were located in the intracellular space wlthout any connection to the Intercellular space. However, we also detected a small number of lumlna that were lined by mlcrovllll, which were present between adjacent tumor cells. Results suggest that the presence of the lntracellular lumlna in tumor cells probably represents a common histopathologic feature of FLC.