Pathology of Choledochal Cysts in Adults and Children : A Prospective Analysis of cases from 2010-2012

OBJECTIVES: To compare the clinical, radiological and pathological characteristics of choledochal cysts in adults and children and describe differences if any. METHODS: All patients with choledochal cyst presenting to General Surgery IV, HPB Surgery and Pediatric surgery between November 2010 and May 2012 were included. 1. Informed consent was obtained from all participants. 2. At laparotomy, bile was obtained from the common duct for measurement of Amylase and Lipase. 3. Intra-operative cholangiogram was performed thereafter. 4. The presence of dysplastic changes and K-ras mutation in the epithelium was noted in the cyst at histopathological examination. 5. Results were analysed to study the association between type of cyst/ junction and the junction length on one hand with the bile Amylase level/ pathological changes/ K-ras mutation in the lining epithelium on the other. RESULTS: 1. Choledochal cysts were commoner in females. 2. Common presenting complaints were pain, vomiting and cholangitis. 3. Coexisting pathology included gallstones, choledocholithiasis and biliary stricture. 4. The commonest cyst type was I in adults and IVA in children. 5. Ultrasonography and MRCP were the common diagnostic modalities used. 6. Long common channel was associated with higher serum/ bile amylase and lipase. 7. MRI and intra-op cholangiogram showed good correlation; MRI identified the common channel better. 8. Children showed higher bile amylase levels. 9. K-ras mutation was uncommon (2/36). 10. Complications and positive bile cultures were commoner in adults. CONCLUSIONS: 1. Choledochal cysts are more common in the female gender. 2. The common presenting symptoms are upper abdominal pain, vomiting and jaundice/cholangitis. 3. Patients with choledochal cyst may exhibit such associated pathology as bile duct/gallbladder/intrahepatic stones, pancreatitis and bile duct stricture. 4. Children tend to have higher bile amylase level which is in keeping with reports from literature where those who were symptomatic at an early age, had higher bile amylase level. 5. The most common diagnostic modality used in these patients was ultrasonography followed by MRCP and intra-operative cholangiogram in that order. 6. The most prevalent cyst types were type I in adults and type IVA in children. 7. Long common channel was more prevalent in children with type I cysts when compared with those who had IVA cysts. 8. Long common channel was associated with higher serum and bile duct amylase levels. 9. MRI and intra-operative cholangiogram exhibited good correlation in the study of the anatomy of the cyst and junction length. 10. The percentage of junctions that could be identified and measured was greater for MRI (100% adults, 81% children) as compared with intra-operative cholangiogram (47% adults and 16% children). This suggests that MRI is the imaging modality of choice in the study of pancreatico-biliary junction. 11. The most common operation after cyst excision in adults was hepatico-jejunostomy while in case of children; the numbers were almost equally divided between end to side hepaticoduodenostomy and hepatico-jejunostomy. 12. Bile cultures tended to be sterile in children and polymicrobial in adults. There was no correlation between post- operative complications and bile culture results. 13. Post operative complications were more frequent in adults as compared to children. 14. The most common post operative complication was a spontaneously resolving bile leak. Other complications included wound infection, secondary haemorrhage, anastomotic leak requiring re-operation, gastric distension and septicemia, all of which were seen only in adults. 15. Drawbacks of the study included small sample size, heterogeneous adult population, nonuniform management protocols, inability to see the common channel in some images, incomplete follow up and low prevalence of K-ras mutation