Which is the most common type of choledochal cyst?

The most common type of choledochal cyst is indeed the first type, which is characterized by a fusiform dilation of the common bile duct (CBD). This type, known as Type 1, accounts for the majority of choledochal cyst cases and often presents with symptoms such as abdominal pain, jaundice, or pancreatitis due to bile duct obstruction or injury.

Type 1 choledochal cysts are typically congenital malformations arising from an abnormality in the pancreaticobiliary junction, leading to an increase in intraductal pressure and subsequent dilation of the CBD. Diagnosis is often made through imaging techniques such as ultrasound or MRI, and the treatment usually involves surgical intervention to relieve symptoms and prevent complications like cholangitis or malignancy.

In contrast, while other types of choledochal cysts exist—such as Type 3 (choledochocele), which occurs in the intraduodenal segment of the CBD, Type 4 (dilation of intra and extrahepatic ducts), and Type 5 (Caroli's disease, which involves cystic dilation of intrahepatic bile ducts)—these are less common and make up a smaller percentage of choledochal cyst cases. Thus, the prevalence