This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Pathology
Most common anterior mediastinal tumour? 
Select and explain. 
A. Thymoma, B. Neurofibroma, C. Pericardial cyst, D. Bronchogenic cyst
A: Thymoma
Answer: A: Thymoma 
Explanation: The designation "thymoma" is restricted to tumors of thymic epithelial cells. Such tumors typically also contain benign immature T cells. The tumors usually occur in adults older than 40 years of age; thymomas are rare in children. Males and females are affected equally. Most arise in the anterior superior mediastinum, but sometimes they occur in the neck, thyroid, pulmonary hilus, or elsewhere.