A 61-year-old man, who is a lifelong non-smoker, was found on routine testing in 2002 to have abnormal liver function tests. Ultrasound examination demonstrated abnormal liver texture. Shortly afterwards he had a significant bleed from an oesophageal varicoele and as a consequence underwent computed tomography (CT) scanning of his thorax and abdomen. A liver biopsy was performed at this time, which showed granulomatous hepatitis. On the basis of this and widespread hilar and mediastinal lymphadenopathy, a clinical diagnosis of sarcoidosis was made. Treatment with systemic corticosteroids resulted in a modest improvement in his liver function and general well being.

Over the subsequent 4 years he developed finger clubbing and progressive exertional dyspnoea with a final exercise tolerance of just 20 m on the flat. He was aware that his dyspnoea improved when lying down. Clinical examination at this time revealed cyanosis, an elevated jugular venous pressure, and a degree of pedal oedema. His chest was clear to auscultation and there were no cardiac or pulmonary bruits.

The patient’s oxygen saturations breathing room air at rest were 84% lying and 68% erect. Arterial blood gases confirmed severe type 1 respiratory failure with an arterial oxygen tension (Pao₂) of 4.8 kPa; this value improved only marginally with the addition of supplemental oxygen. Spirometry showed a mildly obstructive ventilatory pattern with preserved lung volumes. Transthoracic Doppler echocardiography demonstrated normal left and right ventricular anatomy and function and no evidence of tricuspid regurgitation to allow accurate estimation of the pulmonary artery systolic pressure. His chest radiograph, a ^99mTc macroaggregated albumin perfusion scan and CT–pulmonary arteriogram are shown in figs 1 and 2.