Unusual thoracic CT manifestations of osteosarcoma: review of 16 cases.

Pulmonary metastases are common in osteosarcoma and the most common appearance is of multiple well-defined nodules in the lung parenchyma. However, a variety of atypical locations and presentations of osteosarcoma metastasis can occur in the thorax. We present a review of the thoracic CT findings in 16 patients with histopathologically confirmed osteosarcoma with unusual thoracic manifestations. The 16 patients were selected out of a total 136 patients who received a chest CT scan for osteosarcoma during a period of 3 years in a tertiary care hospital. Unusual imaging findings included a solitary large ossified lung mass, ossified mediastinal and hilar lymph nodes, an esophagomediastinal fistula, lymphangitic carcinomatosis, pulmonary artery tumor emboli, a solitary large pleural deposit along the major fissure, multiple pleural deposits, diffuse pleural calcification, pneumothorax, diaphragmatic deposits, an isolated chest wall deposit without lung involvement, and primary osteosarcoma of the rib. Our findings of lymphangitic carcinomatosis in a living patient as well as calcified mediastinal lymphadenopathy leading to esophageal fistula are unique in the literature, and there are only a few case reports of our other findings.