Intrabiliary rupture of hydatid cyst: diagnosis with MRI and hepatobiliary isotope study.

Intrabiliary rupture is the most common complication of hepatic hydatid cyst yet it is unusual, occurring in only 3-17% of cases. The diagnosis is rarely difficult on ultrasound and CT when typical radiological features are present. In rare cases of complete evacuation, when characteristic findings of hydatid cyst are absent or when there is no evidence of the previous existence of liver hydatid cyst, the diagnosis may be difficult. In difficult cases, MRI, MRCP, ERCP and (99)Tc(m)-mebrofenin hepatobiliary scintigraphy are employed. We present a rare case of surgical obstructive jaundice due to rupture of a liver hydatid cyst into the biliary tract and gall bladder, with complete evacuation of its contents leading to misdiagnosis on CT and ultrasound. MRCP and (99)Tc(m)-mebrofenin hepatobiliary scintigraphy were able to establish a firm pre-operative diagnosis.