Protein plugs cause symptoms in patients with choledochal cysts

Symptoms in patients with choledochal cysts are believed to be caused by pancreaticobiliary maljunction. However, this anomaly alone cannot explain the occurrence of symptoms. The aim of this study was to elucidate the etiology of the symptomatology in patients with choledochal cysts.

Clinical data and preoperative and operative cholangiopancreatography were reviewed in 55 consecutive patients with choledochal cysts seen between 1980 and 1996.

The bile duct was significantly larger in the symptomatic phase than in the asymptomatic phase. External biliary drainage resulted in rapid resolution of symptoms in 11 patients. A radiolucent filling defect in the pancreaticobiliary duct was found in 22 patients (40.0%). The defects were in the common channel in 15 patients and near the common channel in 7 patients. Filling defects disappeared spontaneously or after irrigation in 19 patients. In three patients, the material in the common channel removed during surgery was fragile and consisted of more than 98% protein.

The filling defects were protein plugs. The simultaneous occurrence of symptoms and signs may be explained by disturbances in bile and pancreatic secretory flow caused by a protein plug in the common channel.