The author presents the case-history of a typical clinical picture of a rare vascular affection – cystic degeneration of the adventitia of the popliteal artery in a young man. The diagnostic conclusion was reached by means of duplex sonography and angiography of the extremity, the condition was treated by reconstruction surgery. With regard to its long-term effect the author prefers it to some non-surgical procedures which include in particular transluminal angioplasty or sonographically assisted needle aspiration of the cyst.

        Key words: cystic degeneration of the adventitia – popliteal artery – reconstruction