Prenatal diagnosis of a choledochal cyst: a case report and review of the literature.

There are 16 reported cases of prenatally diagnosed choledochal cyst in the literature. We present a new case diagnosed at 29 weeks' gestation by routine ultrasound scanning. At 40 weeks' gestation, a male infant was born by spontaneous delivery. At 16 weeks of age, the patient underwent a laparotomy, which confirmed the diagnosis of a choledochal cyst. The cyst and the gallbladder were removed en bloc and reconstruction of the biliary tree was performed by formation of a retrocolic Roux-en-Y-hapatojejunostomy with an antireflux valve. Histological examination of the cyst showed a thickened fibrous tissue wall with necrotising areas and without epithelial lining. The patient's postoperative course was uneventful. Review of the literature shows that it is possible to make a presumptive prenatal diagnosis of this anomaly as early as 15 weeks' gestation. The differential diagnosis of a sonolucent lesion in the fetus should also include the rare choledochal cyst. Treatment of choice is the radical excision of the cyst with construction of a Roux-en-Y hepaticoenterostomy. Long-term results with this method are very good. Surgery may be instituted at the earliest possible opportunity before severe complications such as cholangitis, liver abscesses, cirrhosis, and malignant degeneration can occur.