Spontaneous regression of symptomatic thymoma caused by infarction.

We herein report a 38-year-old man who had spontaneous regression of a thymoma with repeating episodes of chest pain that initially occurred 2 years earlier when the tumor was 35 mm in the long axis. Left video-assisted thoracoscopic thymothymectomy was performed. Pathology examination showed a thymoma 15 mm in the long axis, classified B2 in the World Health Organization classification and stage II by Masaoka staging. The feeding arteriole of the tumor, occluded by organized thrombi, was suggested to be the cause of coagulation necrosis. The patient recovered well from surgery without complication and with no episodes of chest pain at the 9-month outpatient follow-up.