Primary Extraskeletal Mesenchymal Chondrosarcoma of the Anterior Mediastinum

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Primary extraskeletal mesenchymal chondrosarcoma (EMC) of the mediastinum is an extremely rare disease. To date, only seven cases have been reported in the literature 1-4 since it was first reported by Chetty in 1990. 1 We experienced a case of primary mediastinal EMC presenting as an anterior mediastinal mass, a previously unreported site. Here, we describe the characteristic features of the lesion with a review of the literature to emphasize that EMC should be considered in the differential diagnosis of mediastinal tumors. A 21-year-old woman visited an outside hospital with the chief complaint of intermittent chest discomfort and respiratory difficulty for 2 months. In the medical history, the patient had taken medication for schizophrenia for several years. On the chest computed tomography (CT) scan, the patient had a 13-cm heterogeneous enhancing mass with multifocal calcification in the anterior mediastinum that invaded the pericardium and was associated with massive left pleural effusion. The mass encased the aortic arch and branch along with the left and main pulmonary arteries, but did not appear to be originating from the os-teocartilaginous structures of the thoracic region (Fig. 1A). The patient then underwent a CT-guided needle biopsy, for which a diagnosis of solitary fibrous tumor was suggested on a biopsy. Then, the patient was referred to the Dong-A University Medical Center to confirm the diagnosis and undergo further treatment. Although the tumor could not be resected completely due to the extensive invasion into the main vessels, a surgical excision of the mass along with wedge resection of the left upper lung and partial resection of the pericardium was performed. The tumor at the time of surgery was found to invade the pericardium and to be tightly adhered to the left upper lung. However, it could be easily separated from the adjacent ribs. The resected tumor, measuring 13×7.5 cm, was solid, lobulated, and partially covered by a thin fibrous capsule. On the cut section, the tumor was tan white, and soft to fish-flesh, while the lobulated cut surface exhibited focal areas of irregularly sized glistening cartilage and coarse calcification (Fig. 1B). Microscopically, the lesion was composed of a highly cellular proliferation of undifferentiated round, oval, or spindle-shaped cells with …