(90)
Yttrium (Therasphere)
microspheres administered via hepatic artery are a valuable option for treatment of
hepatocellular carcinoma. This
therapy targets
tumor nodules while largely sparing hepatic parenchyma. This retrospective study examines liver explants from 13 adult patients with
hepatocellular carcinoma who received intrahepatic Theraspheres and subsequently underwent
liver transplantation. Histopathologic and laboratory reviews are performed. Theraspheres preferentially migrated to the lobe(s) supplied by the injected artery branches and frequently localized to
tumors.
Tumors showed a chronology of changes beginning with confluent
necrosis typically accompanied by
hemorrhage and later by fibrinoid change. This was followed by
fibrosis with regenerative activity at
tumor peripheries. Adjacent hepatic parenchyma went through a similar sequence of injury and repair that could lead to markedly fibrotic cirrhotic nodules in the vicinity of treated
tumors. No consistent pattern of
thrombomodulin loss was seen in endothelial cells of the
tumors or adjacent parenchyma, suggesting that direct endothelial cell injury was likely not a major contributor to the necrotic process. However, the pattern of injury and repair is suggestive of a localized and subclinical form of radiation-induced
liver disease. The pathologist should be aware of these changes to distinguish them from the diffuse "radiation
hepatitis" associated with older forms of
radiotherapy.