Spontaneous dissection of the external iliac artery due to fibromuscular dysplasia. A case of spontaneous dissection of the external iliac artery due to fibromuscular dysplasia is presented. In a 45-year-old man with a history of sudden onset of intermittent claudication a dissection of the right external iliac artery was found by duplex ultrasound. The patient, who was first treated with conservative therapy, subsequently required operative treatment because of further progression of the dissection. Considering the age of the patient a retrograde thrombendarterectomy manoeuver over guide wire was performed. Angiographic control at the end of operation demonstrated a good reconstructive result without any changes in the right common iliac artery and the aorta. Histopathological examination of the removed material showed fibromuscular dysplasia of the media. In the postoperative course the patient was clinically asymptomatic with ankle/brachial pressure indices of 1.0 on both legs. But shortly after discharge the intermittent claudication in the right leg recurred. Angiography and duplex ultrasound revealed focal stenosis of the right common iliac artery as well as retrograde dissection of the right common iliac artery extending into the distal aorta. Conservative therapy was recommended to the patient by the local hospital and no further progression of clinical and duplex findings within the last six months was found.