Massive aneurysm in a persistent sciatic artery

Persistent sciatic artery (PSA) is an exceptionally rare embryological vascular anomaly with a reported incidence, based on angiographic series, of between 0.01 and 0.05%. We report a case of a patient with bilateral PSAs and a unilateral 12-cm aneurysm arising from the left PSA. As with our case, most PSAs are among the dominant arteries that supply blood to the lower limb with aneurysm formation occurring in up to 40% of cases. The femoral artery is often hypoplastic. Presentation usually includes symptoms and signs of an enlarged buttock mass, sciatic nerve compression, and distal limb ischemia. An interposition inlay graft is the preferred method of surgical repair. Dissection of the aneurysm is not recommended because of risk of damage to the sciatic artery. Endovascular stent placement is an accepted method of repair but does not deal with any local symptoms of the expanding aneurysm.