Unusual causes of intermittent claudication: popliteal artery entrapment syndrome, cystic adventitial disease, fibromuscular dysplasia, and endofibrosis.

In the general population, vascular causes of exercise-induced limb discomfort are most often the result of peripheral artery disease (PAD) due to atherosclerosis. However, several other clinical entities can often mimic the symptoms of atherosclerotic PAD of the lower extremities, particularly among younger patients with fewer risk factors for atherosclerosis, who often are more athletically fit than patients with PAD. Treatment for these entities often requires percutaneous or surgical intervention. This article reviews four uncommon vascular causes of exercise-induced limb discomfort: popliteal artery entrapment syndrome, cystic adventitial disease of the popliteal artery, fibromuscular dysplasia of the lower-extremity arteries, and endofibrosis of the iliac artery.