Imaging diagnosis of a giant choledochal cyst in an infant.

The usual etiologies of giant abdominal cystic masses in infants are mesenteric cyst, enteric duplication cyst, ovarian cyst in females, cystic lymphangioma, however, the presentation of a choledochal cyst in a gigantic form, is unusual. The primary modality for diagnosis of this entity is ultrasound, followed by MRI. The characteristic ultrasound features of a choledochal cyst are a well-defined cystic lesion which may be found to replace any segment of the biliary tree and is distinctly separate from the gallbladder. The associated anomalies are biliary atresia, gallbladder atresia, hepatic fibrosis and those of the pancreatico-biliary ductal system. MRI with MRCP has a conclusive role in confirming the ultrasound diagnosis. Choledochal cysts are currently classified as proposed by Todani et al, into five types. Herein, we report the case study of a 4-month-old male infant afflicted with a gigantic, Type1 Choledochal cyst, complicated by perforation, which was diagnosed by us at the first instance itself, using ultrasound examination and confirmed by MRI. The diagnosis was further confirmed at surgery and histopathology. The recommended treatment of cyst resection accompanied by a hepatico-jejunostomy bypass procedure, was successfully performed in the reported infant.