**Question:** All of the following are true about Choledochal disease except

A. Extrahepatic bile ducts dilate
B. Choledochal cyst is a congenital abnormality
C. It often presents in adults
D. It is a rare condition

**Correct Answer:** C. It often presents in adults

**Core Concept:** Choledochal disease is a congenital abnormality involving dilatation of extrahepatic bile ducts. It can be classified into four types (Type I to IV) based on the cyst's anatomical location and the presence of a communication with the biliary tree. The disease usually presents in childhood but can also manifest in adulthood.

**Why the Correct Answer is Right:** Choledochal disease is typically seen in pediatric patients due to the abnormal development of the extrahepatic bile ducts. The condition is caused by the cystic duct and cystic artery becoming agglutinated and dilated, leading to the formation of a cyst. While it is a rare condition, it can still occur in adults. The correct answer (C) is incorrect because it is not commonly found in adults, as the disease usually presents in childhood or adolescence.

**Why Each Wrong Option is Incorrect:**

A. Extrahepatic bile ducts dilate: Correct, as this is the primary characteristic of choledochal disease.
B. Choledochal cyst is a congenital abnormality: Correct, as choledochal cysts develop due to abnormal development of the extrahepatic bile ducts.
D. It is a rare condition: Correct, choledochal disease has an estimated prevalence of 1-3 cases per 100,000 individuals, which makes it relatively rare.

**Clinical Pearl:** Understanding the presentation and management of choledochal disease is important for clinicians, as it can lead to complications such as cholangitis, pancreatitis, and even liver cancer if left untreated. Prompt diagnosis and surgical intervention are crucial for preventing these complications.