The multistep process of hepatocarcinogenesis in cirrhosis with imaging correlation.

Hepatocarcinogenesis in the cirrhotic liver has recently become a subject of intense investigation. The development of hepatocellular nodules demonstrating varying degrees of cellular and architectural atypia suggests that these nodular lesions represent a pathway of carcinogenesis in cirrhosis of different etiologies. This pathway involves processes, such as capillarization and neoangiogenesis, leading to a gradual change in blood supply from portal to arterial, as a dysplastic nodule becomes hepatocellular carcinoma. These changes in intranodular blood supply create different enhancement patterns in the two phases of liver circulation after an intravenous contrast injection on multi-phase helical CT or dynamic gadolinium-enhanced MRI. This article reviews the current concepts regarding the vascular changes occurring in dysplastic nodules in the multistep process of hepatocarcinogenesis, along with the associated imaging manifestations. Some practical issues and dilemmas regarding the follow-up and biopsy of these lesions are also discussed.