Endofibrosis of the external iliac artery can occur as a rare complication of high endurance physical activities, particularly cycling, running, and rowing. Symptoms mimic claudication and typically occur with vigorous exercise and improve with rest. Patients can experience thigh pain, swelling and paresthesias in the affected extremity. The diagnosis of endofibrosis is often delayed given the patient's overall normal appearance and lack of significant medical history. This report outlines the presentation and evaluation of a case of endofibrosis of the external iliac artery in an otherwise healthy 42-year-old healthy woman. Her diagnosis was delayed for two years before appropriate diagnostic testing and subsequent surgical intervention allowed for return to a normal, active lifestyle.

Progressive stenosis of the iliac artery, known as iliac artery endofibrosis, is poorly recognized by primary care physicians. It is mainly found in male endurance cyclists who are younger than 40 years of age.^1,2 Because vascular disease is unexpected in these athletes, an arterial insufficiency syndrome is often missed; instead, lower limb and sometimes buttocks pain is attributed to musculoskeletal or neurologic causes. Nonatheromatous functional “kinking” along with stenosis or endofibrosis is the main culprit for claudication.^3–7

The condition is almost certainly underdiagnosed in Canada owing to a lack of recognition and no clear unified strategy for the assessment and management of these patients. The delay in diagnosis is profound, averaging between 12 and 41 months, and diagnosis usually occurs only after many months of failed physiotherapy.¹ The failure to diagnose and treat iliac artery endofibrosis in young athletes has career and social implications that could be markedly reduced with better awareness of the condition among family doctors. According to our literature review completed in February 2015, there are no Canadian data published on this high-yield condition.

External Iliac Artery Endofibrosis (EIAE) is an uncommon disease usually affecting young, otherwise healthy, patients. It usually involves cyclists but cases have been reported in other groups of endurance athletes. The external iliac artery is the most affected anatomical site but other locations are described too. The precise pathophysiology and long-term evolution of the disease still remain unknown. The diagnosis may be challenging and delayed as the patients usually present symptoms only in extreme conditions and physical and instrumental examinations may be normal at rest. We present two cases of young professional cyclists who suffered of exercise-induced leg pain which led them to reduce running. Both patients were firstly treated with balloon angioplasty that rapidly failed to improve their symptoms. The successive open surgery with endofibrosectomy and autologous saphenous vein closure patch completely resolved physical limitations. EIAE is a rare disease that can induce arterial stenosis, thrombosis, dissection and secondary atheroma. After-exercise ankle-brachial index represents a useful diagnostic criterion. Careful observation of angio-CT may strengthen the suspect. Knowledge of the these features allows a better pre-operative assessment and an early effective treatment. Surgical revascularization remains the gold standard approach.