Mycotic Aneurysm of a Persistent Sciatic Artery

An 83-year-old febrile woman presented with leg pain. Her lateral right thigh was swollen, but no neurological or ischemic findings were noted. A computed tomography scan showed an abnormal right internal iliac artery leading directly into the posterior aspect of the thigh, which was determined to be a persistent sciatic artery (PSA) (Picture). The PSA was thrombosed, dilated, and surrounded by enlarged multiple nodular aneurysms, with irregular wall thickening and perivascular edema indicative of infection. Methicillin-resistant Staphylococcus aureus (MRSA) was detected from blood cultures, and an MRSA mycotic aneurysm of a PSA was diagnosed. Her symptoms resolved gradually with intravenous vancomycin. Oral antibiotics were unavailable, so she remains under close observation after 12 weeks of treatment. Aneurysmal enlargement and thromboembolism of a PSA may bring about complications such as limb ischemia and neuralgia (1). The development of a mycotic aneurysm of the type we encountered is notably rare (2).