Most popliteal aneurysms present with a pulsatile mass in the popliteal fossa, which is detectable in nearly half of patients. The mass may be pulsatile or may be nonpulsatile because the aneurysm is filled with thrombus. The proximal type can be found on the medial aspect of the lower 1/3 of the thigh and behind the heart, whereas the central and distal types can only be found behind the popliteal fossa. The diagnosis is usually confirmed based on the following tests: Diagnosis The swollen, pulsating mass in the popliteal fossa is consistent with the pulsation of the heart and can be felt in the lower 1/3 of the inner thigh and behind the proximal type, while the central and distal types can only be felt behind the popliteal fossa. The diagnosis is not difficult to establish based on limb ischemia and compression symptoms, combined with signs such as cold limbs, numbness, weakened or absent pulse, pulsating masses in the popliteal fossa, and eggshell-shaped calcification shadows on X-ray plain film, ultrasound, CT, arteriography, etc. In case of limb ischemia, there may be signs such as pale skin, ulceration or gangrene of the extremity, weakened or absent pulsation of the popliteal artery, and coldness of the limb. If popliteal aneurysm is suspected, the contralateral limb should also be examined to confirm whether there is a combination of aneurysms in other areas. Differential diagnosis When thrombosis or obstruction of the tumor cavity within the tumor is present, only a substantial, non-pulsatile mass can be palpated, which should be differentiated from popliteal lipoma, fibroma, and popliteal cyst.