Bile duct adenoma: imaging features and radiologic–pathologic correlation

Purpose This study aimed to reveal characteristic imaging features of bile duct adenoma (BDA) by radiologic–pathologic correlation. Materials and methods We retrospectively analyzed pathological and imaging findings of seven patients with BDA. Results The median maximum diameter of BDA was 5.5 mm. Six lesions had hemispheric morphology. Seven lesions were located in the liver subcapsular region, and proliferation of bile ductules without atypia and fibrous stroma was observed. Two lesions had different microscopic findings. In both lesions, proliferation of bile ductules without atypia was observed in the margin. In one lesion, the percentage of fibrosis and hyalinization was higher at the center than at the margin. In the other lesion, inflammatory cell infiltration was observed in the center. On contrast-enhanced imaging, BDAs showed hypervascularity in the early phase and prolonged enhancement in the delayed phase. On contrast-enhanced multidetector computed tomography during hepatic arteriography, two lesions showed ring-like enhancement in the first phase and prolonged enhancement in the second phase. These were the different histopathologic features of BDAs between the margin and center. Conclusion Bile duct adenoma can be characterized as a small semicircular lesion located in the liver subcapsular region, which show hypervascularity in the early phase with prolonged enhancement.