Claudication due to cystic adventitial degeneration: a classical differential diagnosis of atherosclerotic peripheral artery disease.

A 50-year-old man, a professional international alpineskiing coach, presented at the Department of Vascular Surgery with a short history of intermittent ischemic muscle pain of the right lower leg. Reversible claudication typically occurred during physical activity and was relieved after a short rest. At the time point of presentation, the subjective limitations, however, were only low. His medicinal history included traumatic knee injuries from skiing accidents that had been treated surgically twice. Clinical examination revealed no palpable mass in the popliteal fossa but loss of foot pulses with knee flexion (Ishizawa sign). In addition, peripheral oscillography revealed a vascular circulation disorder of the right lower limb, and grade I atherosclerotic peripheral artery occlusive disease was clinically suspected.1 Therefore, contrast medium–enhanced computed tomography angiography of the infrarenal arterial vascular tree was performed to assess the degree of suspected atherosclerotic stenoses and to exclude another cause of claudication (eg, a postsurgical popliteal artery stenosis). Computed tomographic angiography with 3-dimensional reconstructions (Figure, A) showed no arterial calcifications and no atherosclerotic plaques but a cystic extraluminal mass along and around the popliteal artery (Figure, B and C, arrows) extending to the tibiofibular trunk (Figure, D, arrows). The diagnosis was cystic adventitial degeneration causing an extraluminal extrinsic compression of the popliteal artery leading to a mild vascular stenosis (Figure, D). Because the subjective limitation was low and the patient did not wish for a surgical vascular patch operation, he was released with the advice for clinical consultation in case the claudication symptoms increased. Cystic adventitial degeneration is a vascular condition characterized by a collection of mucinous material within the adventitia of an affected vessel.2–4 In contrast to atheroscle-