Primary neoplasms of the pulmonary artery are extremely rare and usually are not recognized until autopsy. We present a case in which the correct preoperative diagnosis was established by cardiac catheterization. The hemodynamic and angiographic findings of sarcoma of the pulmonary artery are distinct and should not be overlooked in the evaluation of right ventricular outflow tract obstruction. PRIMARY malignant lesions of the pulmonary artery are extremely rare; to our knowledge, only 68 cases have been reported previously.'-9 Most of these case reports were based on autopsy study, and in only 17 of these patients was the correct antemortem diagnosis suggested. We describe a patient with primary leio-myosarcoma of the pulmonary trunk in whom the pre-operative diagnosis was correctly suggested by cardiac catheterization. Case Report A 51-year-old man was referred to the Mayo Clinic for evaluation and treatment of presumed massive pulmonary thromboembolism. The patient was an active farmer with a smoking history of 25 pack-years. He had no history of leg trauma, deep vein thrombosis or hospitalization. Twelve months before the current examination , the patient had noted the onset of progressive dyspnea on exertion. Six weeks before admission, the patient had complained of right pleuritic chest pain, scant hemoptysis, chronic cough, night sweats, an-orexia and a weight loss of 9.1 kg. Immediately before referral, right-heart catheterization performed with injection of contrast medium into the right atrium demonstrated a large filling defect in the pulmonary trunk, interpreted to be a "saddle embolus." Physical examination revealed that the patient was dyspneic at rest and had a blood pressure of 135/75 mm Hg and a regular pulse of 100 beats/min. There were prominent "V" waves in the jugular venous pulse. A sustained right ventricular lift was present. The pulmonary valve closure sound was accentuated. A grade 3 pulmonary ejection murmur and a grade 2 tricuspid insufficiency murmur were evident. The abdominal examination was unremarkable. No peripheral edema, adenopathy, cyanosis, clubbing or evidence of deep vein thrombosis was noted. Laboratory data included the following: hemoglobin 11.7 g/dl, total iron-binding capacity 208 g/dl, serum iron 34 g/dl, and iron saturation 16%. Circulation 66, No. 3, 1982. 12-channel chemistry group testing, including hepatic and renal function tests, were normal. The ECG showed sinus tachycardia without evidence of right ventricular hypertrophy. Arterial blood gases (breath-ing room air) were Pao, 73 mm Hg, Paco2 34 mm Hg, pH 7.49 and plasma HCO 25 mEq/l. Chest roentgen-ography and tomography of the right lung demonstrated an irregular, thick-walled, cavitary lesion in the superior segment of the right lower lobe (fig. 1). Spu-tum cultures for acid-fast bacilli, fungi and pathogenic bacteria were negative. Results of bronchoscopy with brushings and transbronchoscopic biopsy in the region of the lesion in the right lower lobe were nondiagnos-tic. A search for an occult malignant le...
