[Case of osteosarcoma of the pulmonary artery]

A 49-year-old man was admitted to our hospital for an expanding tumor in the pulmonary artery. He had visited a previous hospital complaining of dyspnea on effort and had syncope 4 months before admission, and pulmonary embolism was diagnosed because enhanced chest CT showed filling defects, with calcification in the pulmonary trunk and left pulmonary artery. Despite thrombolytic and anticoagulant therapy, the filling defects grew and expanded into the extravascular portion. Additionally, CT showed multiple pulmonary nodules and a small calcified nodule in a right-sided back muscle also appeared. At our hospital, FDG-PET showed abnormal uptake in each lesion shown on CT. We then performed a CT-guided needle biopsy of the nodule of the back muscle, which was pathologically diagnosed as osteosarcoma. He was finally given a diagnosis of osteosarcoma of the pulmonary artery. We administered cisplatin and doxorubicin with partial inhibitory effect on tumor growth. Osteosarcoma of the pulmonary artery is extremely rare, and its diagnosis is difficult before surgery or autopsy. To the best of our knowledge there have been no reports of chemotherapy for osteosarcoma of the pulmonary artery.