Metastatic Chondroblastic Osteosarcoma Involving the Thoracic Aorta Managed with Thoracic Endovascular Aortic Repair: A Case Report and Tribute.

Chondroblastic osteosarcoma is a rare and aggressive subtype of osteosarcoma, and thoracic aortic involvement is exceptionally uncommon. We report a 57-year-old male with multifocal metastatic chondroblastic osteosarcoma presenting as a mediastinal mass encasing the descending thoracic aorta. He presented with painful thigh swellings, fatigue, and weight loss for three weeks. His history included right orchidectomy and chemotherapy for a germ cell tumor 30 years earlier, with remission. Biopsy of the thigh lesions confirmed metastatic chondroblastic osteosarcoma. Staging computed tomography revealed an unresectable mediastinal mass encasing the descending thoracic aorta, with intraluminal thrombus causing near-total occlusion. Positron emission tomography-computed tomography demonstrated avidity involving the mediastinal mass and partial uptake in the thrombus. Thoracic endovascular aortic repair relieved the stenosis and enabled systemic therapy. Despite systemic and palliative therapies, the patient succumbed to progressive disease 13 months after diagnosis. This case highlights the role of endovascular repair in malignant aortic involvement.