Which type of choledochal cyst arises from the intraduodenal portion of the common bile duct?
A. Type ICholedochal cysts refer to a spectrum of congenital biliary tract disorders, with a cyst wall composed of fibrous tissue and devoid of mucosal lining. Type I cysts are characterized by fusiform dilatation of the bile duct, type II by isolated diverticula protruding from the wall of the common bile duct, and type III cysts arise from the intraduodenal portion of the common bile duct (also known as choledochoceles). Type IVA consists of multiple dilatations of the intrahepatic and extrahepatic bile ducts, whereas Type IVB involves only the extrahepatic bile ducts. Lastly, type V (Caroli disease) cysts are all intrahepatic, and usually consist of multiple dilatations. Cysts can lead to abdominal pain, cholangitis, pancreatitis, as well as a biliary tract malignancy.