Histopathologic Features of the Popliteal Artery Entrapment Syndrome

Abstract

Surgically occluded popliteal arteries, resected from five patients with clinical and radiologic evidence of the popliteal entrapment syndrome, were examined histologically. Degenerative changes and neovascularization appear to be the initial changes in the adventitia of the artery, which then seem to progress to involve the entire vessel wall. Three distinct stages of progression were identified. Stage 1 is the earliest phase, comprising neovascularization of the adventitia, with no medial fibrosis or destruction. In stage 2 there is transmural vascular proliferation with accompanying fibrous replacement of the media. Stage 3 shows similar neovascularization, with extensive fibrous replacement of the media, fragmentation of the internal elastic lamina, and extensive fibrointimal proliferation, with superimposed thrombus. Recognition of each of the varying stages allows for distinction of this uncommon condition from other clinical mimics of an acutely threatened lower limb.