Recurrent Fever and Biliary Ectasia Leading to the Diagnosis of Caroli Syndrome: A Diagnostic Challenge.

Caroli syndrome (CS) is a rare congenital fibropolycystic liver disorder characterized by non-obstructive intrahepatic bile duct dilatation and congenital hepatic fibrosis, often masquerading as fever of unknown origin. A 38-year-old Hispanic male presented with four weeks of intermittent high-grade fevers and right upper quadrant pain following recent travel to Mexico. An extensive infectious workup was unrevealing, while inflammatory markers were markedly elevated despite normal liver enzyme levels. Cross-sectional imaging revealed multiple intrahepatic cystic dilatations with biliary ectasia, and liver biopsy confirmed congenital hepatic fibrosis, establishing the diagnosis of CS. He defervesced rapidly on empirical broad-spectrum antibiotics. CS should be considered in patients with recurrent unexplained fevers and biliary abnormalities, even when liver enzyme levels are normal, to enable timely diagnosis and surveillance for long-term complications.