[A case of preoperatively diagnosed primary pulmonary leiomyosarcoma].

A 29-year-old woman had been suffering from right back pain for 3 months. Chronic pulmonary thromboembolism was suspected and she was referred to our hospital. She presented with no risk factors for thromboembolism, and during the previous 6 months had lost 4 kg in body weight. Chest radiography showed nodular shadows in the lower field of the right lung. Contrast-enhanced computed tomography demonstrated a filling defect in the right pulmonary artery and nodular lesions in the lower field of the right lung, which were considered to be signs of pulmonary infarction. Absence of perfusion into the right lung was demonstrated by a perfusion scan. Right heart catheterization showed normal pressure in the pulmonary arteries, and pulmonary angiography showed an abrupt cutoff of the right pulmonary artery, which was similar to the finding of pulmonary thromboembolism. A transvenous catheter suction biopsy was performed in the right pulmonary artery and the histopathologic findings yielded a diagnosis of leiomyosarcoma. The patient underwent surgical resection under total cardiopulmonary bypass. A large tumor completely filled the right main pulmonary artery and invaded the posterior wall of the pulmonary trunk close to the left main pulmonary artery. Primary pulmonary leiomyosarcoma is a rare tumor and its prognosis is very poor. Radical surgical resection is the only effective treatment, but early diagnosis is very difficult. Transvenous catheter suction biopsy is a useful procedure for the early diagnosis of pulmonary artery sarcoma.