Giant and complicated variants of cystic bile duct hamartomas of the liver: MRI findings and pathological correlations

Abstract

To describe a new category of liver cyst we propose calling "giant bile duct hamartoma (giant-BDH)" and to provide a more complete record of the magnetic resonance imaging (MRI) features of BDHs with potential for clinical impact. This study was Institutional Review Board (IRB)-approved and Health Insurance Portability and Accountability Act (HIPPA)-compliant. Fifteen patients were identified with surgical liver pathology in keeping with complicated BDH and MRI findings of giant cysts. In all, 14/15 patients presented with pain that resolved in 14/14 with surgery. Imaging features common to pretreatment cysts included sharply defined, lobulated margins with thin, smooth rim-enhancement. Treated symptomatic cysts measured 9.8 cm on average and 21.6 cm maximum. The 14/15 patients had coexistent <2.0 cm BDH. Elevated T1 signal corresponded with hemorrhagic cyst content (10/15 patients); cyst-wall rim-enhancement corresponded with histological findings of inflammation (15/15), fibrocystic changes (12/15), and smaller BDH in the adjacent liver (13/15). Histology of giant-BDH cyst walls corresponded with complicated BDH in 15/15. The incidence of symptomatic-treated BDH at our institution was 0.4%. BDH is a benign hepatic cystic lesion that may undergo cystic enlargement, internal hemorrhage, and clinically present with abdominal pain treatable by minimally invasive laparoscopic fenestration. Complicated giant-BDH coexists with smaller BDH and the MRI features of giant-BDH are characteristic.