2015 Volume 29 Issue 4 Pages 521-526
An asymptomatic 69-year-old man with a history of asbestosis was found to have an abnormal shadow in his left lung field on a chest radiograph. Chest CT revealed an 80×65-mm calcified mass in the dorsal portion of the left thorax. CT-guided needle biopsy revealed osteosarcoma. The tumor showed expansive and non-invasive growth and the adjacent ribs were intact, based on which the tumor was clinically diagnosed as an extra-skeletal osteosarcoma derived from the chest wall, pleura, or lung. FDG-PET and a bone scintigram revealed abnormal accumulation in the tumor but not at distant sites. The patient underwent thoracotomy. The tumor was resected with resection of part of the lung and the 3rd to 6th ribs together due to firm adhesion to the tumor. The tumor showed a solid and well-bordered appearance. Histological examination revealed the proliferation of spindle cells and chondro- and osteo-tissue formation, and the absence of rib and lung involvement was confirmed. Methothelioma-specific markers were negative based on immunohistochemistry. The final pathological diagnosis was extraskeletal osteosarcoma derived from soft tissue of the chest wall. The patient was followed-up without adjuvant therapy. One year after the surgery, tumor recurrence of pleural dissemination was suspected by CT, and so the patient underwent tomotherapy, but no tumor re-growth had been noted as of 1 year after treatment.
