Hydatid cyst of the liver rupturing into the biliary tract--mimicking acute cholecystitis on hepatobiliary scanning.

Two patients presenting with right upper abdominal colicky pain, jaundice, and fever had a hepatobiliary scan using Tc 99m HIDA. The scan was suggestive of acute cholecystitis and a space occupying lesion in the liver. On operation, liver echinococcosis, located in the right lobe rupturing into the biliary ductal system, was found. Intraoperative cholangiography revealed filling defects in the main biliary ducts. Exploration of the common bile duct disclosed daughter cysts and cystic debris. Acute cholecystitis or stones were not found. We conclude that in patients with a clinical picture and HIDA scanning compatible with acute cholecystitis and a space occupying lesion in the liver, the diagnosis of hydatid cyst of the liver which has ruptured into the biliary tract should be considered.