Neoplasm-like Liver Lesions
Neoplasm-like liver lesions are mass-forming lesions that may develop in normal as well as diseased liver. They generally are considered to carry a low risk for neoplastic progression. They may be solid or cystic, solitary or multifocal. Hepatocellular lesions include focal nodular hyperplasia (FNH), a localised hyperplastic mass probably secondary to a vascular insult. Nodular regenerative hyperplasia has a similar pathogenesis but affects the liver more diffusely. In some cases, areas of nodular regenerative hyperplasia become dominant and form nodular lesions, which may be evident on imaging and cause diagnostic difficulties. Large regenerative nodules usually are observed in cirrhosis. They are similar to the background regenerative nodules, although larger, and are visible macroscopically in surgical specimens or on imaging. Inflammatory pseudotumour is a localised mass-forming inflammatory reaction. It usually is associated with other conditions, although in rare cases it has been shown to be neoplastic.