Anatomy and Imaging of Accessory Liver Lobes: What Radiologists Should Know

Although the liver may present a range of congenital anomalies, often involving shape irregularities or the number of lobules, less common variations include the presence of accessory liver lobes (ALL), consisting of a supernumerary lobe of normal hepatic parenchyma in continuity with the liver. This paper reviews the embryology, frequency, anatomy, and types of ALL. Furthermore, we describe computed tomography and magnetic resonance imaging findings in a range of such cases, including those simulating disease or presenting with complications. Knowledge about ALL may facilitate imaging interpretation of such alterations, avoiding inappropriate additional work-up and unnecessary interventions.