An Unusual Invasive Ectopic Thymoma in the Thyroid and Anterior Mediastinum

An 81-year-old woman with a 2-year history of dysphagia detected a cervical mass. Computed tomography showed a thyroid tumor extending through the superior and anterior mediastinum. Analysis of an incisional biopsy specimen revealed a thymoma. Total resection of the thyroid and mediastinal tumor was performed. The thymoma invaded the anterior tracheal wall and left brachiocephalic vein. Pathologic examination revealed thymoma type B1 concomitant with B2 and B3 (World Health Organization classification), Masaoka IVb, and T3 N2 M0-IVb, with cervical lymph node metastasis. Clinicians must be cautious during radical operations for invasive ectopic thymomas.