Mediastinal chondrosarcoma is an exceedingly rare case, particularly in posterior mediastinum. In this case, a 28 years old male was referred to Cipto Mangunkusumo Hospital, Jakarta with chief complaint of worsening dyspnea since one month complementedwith mild cough and fever. Thorax rontgen and CT scan revealed mediastinal mass and pneumothorax. More thorough EBUS TBNA, bronchoscopy, esophagoscopy, EUS and biopsy were performed. From EBUS TBNA an image of a mass similar to thymoma was discovered, but immunohistochemistry test could not be carried out due to inadequate sample. Later EUS imaging revealed chondrosarcoma. The diagnosis of this tumor was difficult because small biopsy or needle biopsy usually warranted only small amount of tissue leading to false interpretation of chondrosarcoma as type A thymoma, solitary fibrous tumor or synovial sarcoma. The patient went through five sessions of radiotherapy, however thoracotomy was not performed because endotracheal intubation was not feasible to execute. The patient was let out with plans of chemotherapy.
Key words: Diagnosis, chondrosarcoma.