In a child under 10 with abdominal pain, jaundice, and a palpable mass in the right upper quadrant, what is the most likely diagnosis?

In a child under 10 presenting with abdominal pain, jaundice, and a palpable mass in the right upper quadrant, biliary cysts (choledochal cysts) are a significant consideration. These cysts can lead to obstruction of bile flow, which results in jaundice due to elevated bilirubin levels. The palpable mass is often related to the cystic dilation of the biliary tree, which can be felt on physical examination.

Biliary cysts are congenital abnormalities that can occur in pediatric patients, and they are characterized by the presence of abnormal cystic dilations of the bile ducts. When they occur, they can lead to complications like cholangitis, pancreatitis, or biliary obstruction. Diagnosis is typically confirmed through imaging studies, such as ultrasound or MRI, which can visualize the cyst and assess for any potential complications.

In contrast, hepatic tumors and pancreatitis may also present with abdominal pain and jaundice but typically do not present with a well-defined palpable mass in the same manner as biliary cysts. Cholecystitis, while it involves the gallbladder and can cause pain and jaundice, is less common in children, especially at this young age, and would usually not present with a mass that could