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
Which of these is the most common cause of a posterior mediastinum mass in children? 
Select and explain. 
A. Rhabdomyoma, B. Duplicated cyst of the esophagus, C. Thymoma, D. Neuroblastoma
D: Neuroblastoma
Answer: D: Neuroblastoma 
Explanation: Ans. D. NeuroblastomaSeveral causes of posterior mediastinum mass in children are known; including neurogenic tumors (most common cause), foregut cyst, germ cell tumors, lymphangiomas and lymphomas. Since the most common neurogenic tumor in children is neuroblastoma, it should be the correct answer.