Abstract
We report a case of primary osteosarcoma of the lung. A 73-year-old man was referred with an enlarging nodular shadow on chest CT. The nodule enlarged from 10 to 20 mm in five months, and malignancy was suspected. Partial resection of the left lung was performed. Pathological examination of the tumor was hamartoma of the lung. Approximately one year later, a new nodular shadow was detected in S1+2 of the left lung. The nodule enlarged from 10 to 20 mm in seven months, and a new nodule measuring 10 mm in diameter developed in the same area. Partial resection of the left lung was performed again. Pathological findings of these tumors were similar to the previously resected tumor. Our diagnosis at this time was multiple chondromatous hamartomas of the lung. However, he experienced abdominal pain six months later. A new large mass was identified in the right adrenal gland and multiple nodules were found in the bilateral lungs. A fine needle biopsy of the right adrenal mass established a pathological diagnosis of osteosarcoma. The pathological finding of the mass was similar to the pulmonary tumors, and our diagnosis was corrected to primary osteosarcoma of the lung and multiple metastases. Primary osteosarcoma of the lung is an extremely rare disease and difficult to diagnose.
