Cystic Adventitial Disease Presenting as Occlusion of the External Iliac Artery: A Rare Manifestation

Cystic adventitial disease (CAD) is a rare, non-atherosclerotic cause of peripheral arterial disease characterized by mucinous cyst formation in the adventitial layer of arteries; with approximately 80% to 90% of cases involving the popliteal artery. We describe a case of CAD presenting in a female with left external iliac artery occlusion and intermittent claudication, for whom an intra-operative diagnosis of CAD of the ilio-femoral segment was made. A 37-year-old mother-of-two was referred to a Vascular Surgeon with a 3 to 4-year history of progressive intermittent claudication. A computed tomography (CT) angiogram demonstrated a left external iliac artery occlusion. Given the location of the lesion, the absence of cardiovascular risk factors and the patient's history of cycling, a diagnosis of left external iliac artery occlusion secondary to arterial endofibrosis or spontaneous arterial dissection was thought to be likely. A left Rutherford-Morrison incision was made and an extraperitoneal approach used to expose the left iliac system. A cyst was opened and marsupialized along the superior aspect of the external iliac artery, releasing gelatinous material. A provisional intra-operative diagnosis of CAD was made. The patient was systemically heparinized and an external iliac to common femoral artery bypass was performed using reversed ipsilateral greater saphenous vein. CAD primarily involves the popliteal artery. Under 40 cases of CAD with iliofemoral involvement have been reported. Our case is unusual given the location of CAD, as well as its occurrence in a female. Management options for similar cases have been described in the literature ranging from cyst excision and arterial patching, to interposition bypass and even exclusion bypass, in the case of longer segment occlusions. In our case, an exclusion bypass was deemed the most appropriate treatment given the extensive length and complete occlusion of the external iliac artery.