Large Regenerative Nodules and Focal Nodular Hyperplasia-Like Lesions: Definition, Pathogenesis, and Imaging Findings

Focal nodular hyperplasia-like (FNH-like) nodules are hepatocellular lesions with similar radiologic and pathologic features as typical FNH but occur within an abnormal liver. They arise due to alteration of hepatic vasculature at both the microscopic and macroscopic levels. Although these nodules are not thought to have malignant potential, their imaging features overlap with premalignant and malignant lesions including hepatocellular carcinoma (HCC) and arise in patients who may be at risk for HCC, posing a diagnostic and management dilemma. It is important to consider these benign entities when reviewing liver imaging of patients at risk for HCC to reduce unnecessary interventions.