This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oncology, Subject name: Medicine
Most common anterior mediastinal tumour is 
Select and explain. 
A. Thymoma, B. Neurogenic tumor, C. Lymphoma, D. Teratoma
A: Thymoma
Answer: A: Thymoma 
Explanation: (Thymoma): {2181- H 18th edition)MEDIASTINAL MASSESAnterior mediastinumThymoma (Most common)***LymphomaTeratomatous neoplasmsThyroid massesMiddle mediastinum- Vascular masses (Most common)**- Lymph node enlargement from metastasis or granulomatous disease- Pleuropericardial and bronchogenic cystsPosterior mediastinum- Neurogenic tumours (Most common)**- Meningoceles, meningomyelocele- Gastroenteric cysts- Esophageal diverticula* Investigation of choice - CT-scan* Definite diagnosis - Mediastinoscopy or anterior mediastinotomy