In current medical practice new disease entities are encountered scarcely. However, sometimes due to progress in knowledge and especially due to application of new diagnostic techniques, unknown diseases may still be found and unravelled. The current study serves as an example.  This study started with a case report on a female endurance athlete, who suffered from progressive exercise-related leg complaints. She had visited eight different doctors before her complaints were identified as intermittent claudication. Only after this recognition, a stenotic lesion was demonstrated in the left external iliac artery with both echo-Doppler examination and arterial digital subtraction angiography. This lesion was treated successfully by vascular reconstruction. The major problem in diagnosing this type of patients seemed to be that both doctors and patients are unaware of the existence of these problems.