A 63-year-old retired male airline pilot was referred to our Cardiac surgery centre reporting a history of tiredness, exertional, breathlessness and chest tightness (Class II New York Heart Association limitation). His past medical history included pre-diabetes, benign prostatic hyperplasia, and TIA with no focal neurological deficit.
The initial imaging revealed thickening in the proximal main pulmonary artery which was avid on PET. This extended into the right and left pulmonary arteries. A CTPA revealed a large filling defect in the main pulmonary trunk that extended into the left and right main pulmonary arteries. The patient was also staged with magnetic resonance imaging (MRI) of the head and a PET scan which were negative for distant metastasis but suggestive of large vessel vasculitis in the pulmonary artery. The patient also had an elevated ESR, this guided initial high dose steroid treatment.
The patient responded initially to high dose steroid therapy– this led to a brief improvement of symptoms and reduction in ESR. He was re-imaged and there appeared to be no radiological improvement of the defects and his symptoms began to progress (Fig. 1). He eventually was referred to our centre for further investigation.
A transthoracic echo revealed severe pulmonary stenosis (PV max 4.67m/s PV max PG 87mmHG) and an echogenic area around the pulmonary valve. The RV was shown to be moderately impaired and hypertrophied with PA pressures of 61mmHg. The left ventricle appeared preserved in size and function with an ejection fraction of 60–65%.
The suspicion of pulmonary artery sarcoma (PAS) increased, and he was discussed at the Pulmonary Vascular Disease MDT. Collectively the decision was made for pulmonary thromboendarterectomy and pulmonary valve replacement. Upon attendance to our centre the patient revealed his symptoms had progressed over the 2-month period since his initial investigations from New York Heart Association (NYHA) class II to class III.
The surgery was performed on cardiopulmonary bypass using the ascending aorta for arterial return and venous drainage via a two-stage cannula in the right atrium with a separate SVC cannula positioned through the body of the right atrium. Cooling was commenced to 20 degrees. Both pulmonary arteries were opened simultaneously for access under the aorta.
The right main pulmonary artery was exposed between the aorta and the superior vena cava. There was mild collateral flow observable. Within the right main PA was some central white/grey tumour like tissue in continuity with the main PA. Excellent clearance was achieved of upper lobe, middle lobe, and lower lobe (Fig. 2 and Fig. 3).
The left main pulmonary artery was opened with a longitudinal arteriotomy extending proximally to the pulmonary valve. There was minimal collateral flow with grey tumour like material obliterating the lumen starting from the leaflets of the pulmonary valve. Good clearance was achieved in continuity with the right PA. The Pulmonary valve was examined and was found to be a tri-leaflet valve with poorly defined left, right and posterior cusps with obvious stenosis. The excised PV was replaced with a 25mm Perimount magna bioprosthesis and the artery was closed with a bovine pericardial patch. Total bypass time was 301 minutes with a total deep hypothermic circulatory arrest time (DHCA) time of 16 minutes, cross clamp time was 102 minutes.
Pulmonary artery sarcoma was diagnosed after consultation with the histopathology services. Histopathology results from the right and left pulmonary artery casts showed both specimens to have extensive variable cellular intimal thickening by tumour composed of spindle and cuboidal cells with some accentuation beneath the luminal surface. There was a surrounding vascularised fibrous stroma. The cells showed weak patchy staining for actin and CD31 but not CD34 or desmin. The appearances are in keeping with an intimal sarcoma. The pulmonary valve had focal involvement of the valve by tumour cells.
After this diagnosis the patient was referred to medical oncology for discussion of further adjuvant chemotherapy.