Thoracic Chordoma Misdiagnosed as Primary Adenocarcinoma of the Mediastinum.

Chordoma is a rare malignant bone tumor originating from the embryonic notochord. Herein, we present a case of thoracic chordoma located at T3-T5 that was misdiagnosed as primary mediastinal adenocarcinoma. The patient underwent neoadjuvant chemoradiation and the disease showed little response. Due to vertebral body invasion, we performed en bloc mass removal and partial corpectomy (T4-5) in collaboration with orthopedic surgeons.