Fibropolycystic liver diseases, also known as ductal plate malformations, are a group of associated congenital disorders resulting from abnormal development of the biliary ductal system. These disorders include congenital hepatic fibrosis, biliary hamartomas, polycystic liver disease, choledochal cysts and Caroli disease. Recently, it has been thought to include biliary atresia in this group of diseases, because ductal plate malformations could be implicated in the pathogenesis of this disease. Concomitant associated renal anomalies can also be present, such as autosomal recessive polycystic kidney disease (ARPKD), medullary sponge kidney and nephronophthisis. These disorders can be clinically silent or can cause abnormalities such as cholangitis, portal hypertension, gastrointestinal bleeding and infections. The different types of ductal plate malformations show typical findings at magnetic resonance (MR) imaging. A clear knowledge of the embryology and pathogenesis of the ductal plate plays a pivotal role to understand the characteristic imaging appearances of these complex diseases. Awareness of these MR imaging findings is central to the detecting and differentiating between various fibropolycystic liver diseases and is important to direct appropriate clinical management and prevent misdiagnosis.

Hepatobiliary fibropolycystic diseases are a unique group of entities involving the liver and biliary tract, which are caused by abnormal embryologic development of the ductal plates at various stages. We experienced strange hepatobiliary fibropolycystic diseases with a complex mass composed of malformed ducts and biliary cysts, which did not belong to, and were different from, previously known malformations. They were unique in imaging and histologic features. We herein report three cases of monosegmental hepatobiliary fibropolycystic disease mimicking a mass.