This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastro Intestinal System, Subject name: Pediatrics
A 5 year boy presented with massive hematemesis. He is not febrile. Per abdomen examination revealed massive splenomegaly without hepatomegaly. Most probable diagnosis would be: 
Select and explain. 
A. Non-cirrhotic portal fibrosis, B. Extrahepatic portal venous obstruction, C. Budd-Chiari syndrome, D. Hepatic carcinoma
B: Extrahepatic portal venous obstruction
Answer: B: Extrahepatic portal venous obstruction 
Explanation: Ans. B. Extrahepatic portal venous obstructionExtrahepatic obstruction is the most common cause of portal hypertension in children. Patients with extrahepatic portal venous obstruction usually present at about 5-6 years with hematemesis with or without melena. Splenomegaly is almost universal in patients with EHPVO and size of spleen is usually dependent on the duration of the illness. Liver is usually normal in size. Ascites is usually rare.