[Solitary ectopic thymoma at ligamentum arteriosum; report of a case].

We report a case of solitary ectopic thymoma at the ligamentum arteriosum, which was resected with thoracoscopic surgery. A 62-year-old male patient received chemoradiation therapy for laryngeal cancer approximately 1 year before. The present computed tomography scan indicated a mass (diameter, 2 cm) at the ligamentum arteriosum. Furthermore, positron emission tomography showed an abnormal accumulation on the mass. Malignant lymphoma and laryngeal cancer with lymph node metastasis were suspected, and thoracoscopic surgery was performed. The tumor had a clear margin;therefore, it could be extirpated easily. The results of the postoperative pathological examination indicated that the tumor was an ectopic thymoma. The patient was discharged 3 days after the surgery because he showed good clinical course and was kept under careful observation.