This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Childhood Tumors, Subject name: Pediatrics
[{'content': "The most common presentation of a child with Wilms' tumor is: \nSelect and explain. \nA. As asymptomatic abdominal mass, B. Hematuria, C. Hypertension, D. Hemoptysis due to pulmonary secondary", 'role': 'user'}, {'content': "Answer: A \nExplanation: a. As asymptomatic abdominal mass(Ref: Nelson's 20/e p 2466)Most common initial clinical presentation for WT is incidental discovery of an asymptomatic abdominal mass by parents while bathing or clothing an affected child or by a physician during a routine physical examination;Hypertension is present in 25% of tumors at presentation and has been attributed to increased renin activity.Abdominal pain, gross painless hematuria, and fever are other frequent findings at diagnosis.", 'role': 'assistant'}]