[Diagnosis of pleural cavity extraskeletal osteosarcoma: a case report and literature review].

OBJECTIVE: To describe the manifestations and diagnosis of pleural cavity extraskeletal osteosarcoma (ESO). METHODS: One case of ESO diagnosed at the Research Institute of Tuberculosis, 309th Hospital of PLA was reported. Six cases reported in the literature were reviewed. RESULTS: Chest CT of a middle-aged man revealed an enormous heterogeneous neoplasm, about 10.9 cm x 9.2 cm x 17.7 cm in size, in the left pleural cavity. There was abundant calcification in the tumor, with signs of invasion into the diaphragm and the pleura. Pleural effusion of the left thoracic cavity was also seen on the chest CT. Osteosarcoma was confirmed by pathological study after surgical resection of the tumor. CONCLUSIONS: ESO is a rare malignant soft tissue sarcoma. Pleural cavity ESO is insidious and imaging studies often reveal a huge mass with abundant calcification. The differential diagnosis includes benign and malignant diseases of the thorax.