Invasive Medullary Type A Thymoma With Recurrent Distant Metastases

Thymomas are rare epithelial mediastinal tumors showing a certain propensity for local and intrathoracic recurrences. Otherwise, extrathoracic metastases are very rarely reported and are usually associated with type B thymomas or thymic carcinomas. We present a challenging patient with an invasive (Masaoka-Koga stage IIb) medullary type A thymoma with recurrent extrathoracic metastases (pulmonary and vertebral localizations occurring 2 and 7 years after the initial radical thymectomy, respectively). Despite type A thymoma being considered a low-grade malignancy with a scarce propensity to recurrence, the present case should alert clinicians to the possibility of bone metastasis. Long-term follow-up in this slow-growing neoplasm is then mandatory.