We report an unprecedented case of ectopic thymoma in a young adult. A
33-year-old male presented with a 10-day history of non-productive cough and
fever. Investigation revealed mediastinal widening without pulmonary
involvement. Computed tomography showed a large mass-14.8 × 10.8 ×
8.4 cm-in the mid-posterior mediastinum, and a biopsy obtained by video-assisted
thoracoscopy indicated that the mass was a tumor. Immunohistochemistry showed
combined thymoma type AB1. Because of the considerable proportions of the tumor
and its close proximity to major structures, the patient was treated with
chemotherapy.