Slow growth rate in a rare isolated external iliac aneurysm

A 91-year-old man was referred for an asymptomatic saccular left external iliac aneurysm. Comorbidities included hypertension, hyperlipidemia, peripheral arterial disease, prior radical prostatectomy with bilateral pelvic lymphadenectomy for prostate cancer, left partial nephrectomy for small renal cell carcinoma, and fundoplication for Barrett's esophagus. Review of prior computed tomography scan of the abdomen revealed that the aneurysm had been present for the last 24 years (measuring 1.6 cm in 1999) with slow growth until 2023 (measuring 2 cm). On surveillance imaging the next year, the maximum diameter had increased to 2.8 cm. He was treated successfully with an endograft limb. Isolated external iliac artery aneurysms are extremely rare, and this single case report supports that these have a very slow growth rate.