Popliteal artery aneurysms (PAAs) are the most common peripheral arterial aneurysms, predominantly affecting older males. They carry risks of thromboembolism, distal embolization, limb ischemia, and amputation, with bilateral involvement in up to 50% of cases. Current management is largely diameter-based, with repair typically recommended at ≥20–25 mm or in symptomatic patients. However, large duplex ultrasound and CT angiography series report considerable variability in thrombus burden and embolic events at similar diameters, while computational models demonstrate that aneurysm geometry influences flow dynamics. The clinical relevance of aneurysm length and inter-limb asymmetry remains less well defined, particularly in cases with marked morphologic disparity. During routine lower limb dissection of an 83-year-old male cadaver, bilateral PAAs were identified within the popliteal fossae. Caliper measurements demonstrated diameters of 23.46 mm (right) and 34.80 mm (left), both exceeding repair thresholds, with substantial length asymmetry (32.34 mm vs 73.41 mm). While most reported PAAs are relatively focal, the left-sided aneurysm demonstrates pronounced longitudinal extension, representing a morphologic extreme compared to imaging series. Both aneurysms were fusiform and contained gross thrombus without rupture or calcification. Measurements were obtained on formalin-fixed specimens, which may affect vessel dimensions. No additional aneurysmal disease was identified. Clinically, both aneurysms would meet criteria for repair; however, the marked elongation of the left-sided lesion may confer disproportionately higher embolic risk. Hemodynamic studies link increased aneurysm length to reduced wall shear stress and prolonged flow residence time, promoting thrombus formation. This raises the possibility that geometrically complex aneurysms represent a higher-risk phenotype not captured by diameter alone. As a cadaveric case, no outcomes can be assessed; this report serves as an anatomical and pathophysiologic illustration. Future prospective imaging cohorts correlating aneurysm geometry with thromboembolic events, alongside computational modeling, are needed to determine whether length and asymmetry should refine risk stratification.
