A Rare Case of Iliac Saccular Aneurysm Communicating with a Transplant Renal Artery.

BACKGROUND Isolated iliac aneurysms are rare. Although they grow very slowly, they can rupture when large enough. Rarely, they rupture into an adjacent organ, such as the colon, the bladder, or even an adjacent vein. Cases of aneurysms rupturing into or communicating with an adjacent vein, leading to an arteriovenous fistula, have been reported. However, reports of aneurysms that rupture and communicate with another adjacent artery have not been found in the literature. CASE REPORT A 52-year-old man who underwent a renal transplantation in the left iliac fossa 21 years ago was admitted for chronic left lower abdominal pain that began 1 year ago. He did not have a history of any invasive procedures or severe trauma after the renal transplantation. Duplex ultrasound showed an oval-shaped hypoechoic structure adjacent to the left external iliac artery (EIA), with a swirling motion of blood flow inside. Computed tomography angiography showed an aneurysm of the left EIA, with a size of 35×34×47 mm, closely adjacent to or even communicating with the transplant renal artery (TRA). There was calcification in the aneurysm wall, without surrounding hematoma. The aneurysm was considered to be a true aneurysm, not a pseudoaneurysm. Endovascular therapy was performed. Digital subtraction angiography confirmed the communication between the aneurysm and the TRA. After the EIA was reconstructed with a covered stent, no leakage was demonstrated; however, contrast still flowed into the aneurysm though the TRA. A second covered stent graft was implanted in the TRA. Subsequently, the aneurysm was successfully excluded. CONCLUSIONS The pathogenesis of this strange aneurysm communicating with another adjacent artery is not well established. Stenting of multiple arteries was needed to treat this aneurysm.