ABSTRACT
Thymomas are the most common type of mass found in adult anterior mediastinal masses. Thymomas typically metastasize to the ribcage because of their slow growth and affinity for local invasion. Far metastases are rare, with the brain as the most commonly metastasized area. Bone metastases of thymomas are usually observed in the calvarium. A 60-year-old patient, who presented with metastatic mass lesions that developed 18 months after undergoing a surgery for mediastinal thymomas in the sacrum and iliac bones detected by computed tomography, magnetic resonance imaging, and histopathology, is the first mediastinal thymoma case with metastasis to the sacrum in the literature.