Pulmonary arteriovenous fistula. 
Two cases of congenital pulmonary arteriovenous fistula are reported.  Both patients had cyanosis and clubbing of their fingers and toes and also dyspnoea at exercise.  Diagnostic procedures included cardiac catheterization and pulmonary angiography, and in both patients a solitary pulmonary arteriovenous fistula could be demonstrated.  Lobectomy was performed in both cases, and at follow-up the patients were quite well with normal laboratory tests.