Pulmonary metastasis from encapsulated cervical ectopic type a thymoma

A 39-year-old woman underwent tumor resection for an encapsulated cervical ectopic thymoma (type A). However 7 years after complete resection, computed tomography (CT) screening detected a 9-mm pulmonary nodule, which was completely resected and was diagnosed as a metastasis from the ectopic thymoma. There have been few reports on cervical ectopic thymoma metastasizing to a distant site and, to the best of our knowledge, this is the first case report of a cervical ectopic type A thymoma with distant metastasis.