A 63-yr-old black female, with a 1-yr history of hepatitis C and ascites was referred to an expert centre with suspicion of portopulmonary hypertension (PPHTN). Her poor condition made a rapid diagnosis imperative and precluded a normal diagnostic work-up. Echocardiography confirmed severe pulmonary hypertension (PH). A hepatic scintigraphy and an abdominal echo-Doppler study excluded liver cirrhosis and portal hypertension. Cardiac magnetic resonance imaging showed marked dilation of the right ventricle with significant hypertrophy of the free wall, a finding that is uncommon in idiopathic pulmonary arterial hypertension or PPHTN. Right heart catheterisation demonstrated severe pre-capillary PH without response to acute vasodilator testing. Finally the patient underwent computed tomography angiography, which showed marked dilation of the pulmonary artery without thromboembolic disease and, unexpectedly, a partially calcified large patent ductus arteriosus. The correct diagnosis of the underlying cause of pulmonary arterial hypertension is essential. Patients with underlying heart defects may have an atypical presentation and be referred to expert centres with an incorrect diagnosis. A full investigation is necessary; careful examination of right ventricular anatomy can provide clues about the aetiology of PH, and it is important to exclude intra- and extracardiac shunts during haemodynamic studies.