Efficacy of anomalous pancreatic drainage in choledochal cysts correlates with age of presentation and suggests etiology.

The etiology and pathogenesis of choledochal cysts, although frequently debated, are as yet unknown. Findings in three recent patients suggest a possible etiology that may also explain the variability in age at presentation. Each of these patients (ages 12 months, four years, and ten years) was found to have an Alonso-Lej Type I cyst and at operation had an absence of the distal intraduodenal common bile duct, suggesting the lack of a common channel with the main pancreatic duct. Partial decompression of the anatomically obstructed bile duct was afforded by an anomalously high insertion of the accessory pancreatic duct and communication with the duodenum by way of the main pancreatic duct. All patients were managed by excision and retrocolic choledochojejunostomy. The efficacy of decompression correlated with the age of presentation and size of the cyst. These findings suggest agenesis-atresia of the distal common bile duct as one possible etiology of choledochal cysts and may explain the variable age at presentation.