Intrabiliary rupture of hepatic hydatid cyst: multidetector-row CT demonstration

Rupture of a hydatid cyst into the biliary tract, also known as cystobiliary communication, is the most common complication of hepatic hydatid cyst. This may lead to obstructive jaundice, pancreatitis, cholangitis, and sepsis with high mortality. Imaging plays an important role in the preoperative diagnosis of this condition which facilitates its management. We studied six patients with rupture of hepatic hydatid cyst into a large bile duct in whom multidetector-row CT (MDCT) suggested the diagnosis. The imaging findings included a single hepatic cyst less than 10 cm in diameter in all the cases; interruption of the cyst wall adjacent to a bile duct signifying cyst-bile duct communication was seen in five patients. The common bile duct was dilated in all the patients, with linear membranes in four and diffuse irregular high dense intrabiliary material observed within the common bile duct in two of them. Intrahepatic ducts were dilated in all the six cases and two patients showed linear dense contents within distended gallbladder. Subcapsular and intrathoracic rupture was associated in one patient each. MDCT demonstration of hydatid cyst in the liver together with a dilated common bile duct and distended gallbladder containing high density hydatid material suggest rupture of the cyst into biliary tree. MDCT enhances demonstration of the dilated common bile duct with hydatid material inside. The diagnosis is reinforced by the demonstration of the cystobiliary communication itself.