Pulmonary arteriovenous malformation. Progressive enlargement with replacement of the entire right middle lobe in a patient with concomitant mitral stenosis.

OBJECTIVE

To present a case of pulmonary arteriovenous malformation (AVM) that showed progressive enlargement in a patient with concomitant rheumatic mitral stenosis.

CLINICAL FEATURES: A 73-year-old woman first presented eight years ago because of an uncomplicated acute myocardial infarction. She was noted to have rheumatic mitral stenosis. Six years later, she developed symptomatic sick sinus syndrome for which a permanent pacemaker was implanted. Chest x-ray revealed new development of an opacity in the middle zone of the right lung. Two years later, she was admitted to hospital because of progressive dyspnoea. Chest x-ray showed further increase in size of the right middle zone opacity.

OUTCOME: She died of cardiopulmonary failure on the 18th day in hospital. Autopsy revealed a pulmonary AVM, replacing the entire right middle lobe.

CONCLUSION

The elevated pulmonary vascular resistance caused by mitral stenosis may have increased the preferential flow of blood through the AVM, leading to its rapid enlargement. Patients with concomitant pulmonary AVM and mitral stenosis need to be recognised, as close follow-up and early treatment may be desirable.