Cirrhosis and pre-neoplastic lesions

Cirrhotic livers are characterized by irreversible remodeling of architecture with bridging fibrosis, vascular reorganization and formation of hepatocellular nodules, which are classified histologically as either regenerative or dysplastic lesions. The differentiation of these lesions is important because regenerative nodules (RNs) are benign, whereas dysplastic nodules (DNs) are premalignant. Pathologically, hepatocarcinoma (HCC) develops in a multistep fashion in the following sequence: from low-grade dysplastic nodule (LGDN) to high-grade dysplastic nodule (HGDN), small HCC and, finally, large HCC. Differentiation between DN and early HCC is the most important issue in the clinical setting. This article reviews the current concepts regarding the multistep process of hepatocarcinogenesis, along with the associated histologic and MRI manifestations.