Abstract
Cystic adventitial degeneration of the popliteal artery is a rare disease wherein cysts are formed within the adventitia of the popliteal artery, leading to narrowing of the arterial lumen and causing symptoms of lower limb ischemia. In the present report, we describe a case of cystic adventitial degeneration of the popliteal artery, which presumably occurred due to the formation of a fistula connecting the cyst with the knee joint. A 71-year-old man presented to our hospital with a chief complaint of intermittent claudication of the left lower limb. In the left lower limb,the ankle brachial pressure index was as low as 0.53, and magnetic resonance angiography indicated severe stenosis of the left popliteal artery above the knee. Arteriosclerosis was suspected, and a balloon dilation procedure was performed; however, early recurrence of symptoms and re-stenosis subsequently occurred. The findings of contrast-enhanced computed tomography suggested the presence of cyst formation. Thus, cystic adventitial degeneration of the popliteal artery was suspected, and surgical treatment was performed. Intraoperatively, we observed that a fistula had formed between the cyst and the knee joint. Therefore, the treatment consisted of ligation and resection of the fistula, resection of the popliteal artery and the cyst, and revascularization using the great saphenous vein. Since the causes of adventitial cysts are currently unknown, careful attention should be paid to the formation of fistulas that connect the cyst with joints, in order to prevent recurrence.
