Intraparenchymal renal artery aneurysms. Case report with review and update of the literature.

Increased interest in aneurysms involving the renal artery and its branches has occurred during the past 3 decades. The prevalence of renal artery aneurysms is approximately 0.01%-1% in the general population as well as 2.5% in hypertensive patients undergoing angiography. Intraparenchymal renal artery aneurysms (IPRAAs) are rare since being detected in less than 10% of patients with renal artery aneurysms. The Authors report an unusual case of multiple small intrarenal artery aneurysms associated with a large IPRAA located in the mid portion of the right kidney. Usually, IPRAAs are secondary to diseases or injuries of the kidney vascular network. They are classified as true, false, saccular, fusiform, dissecting, and microaneurysms. Potential complications of IPRAAs include peripheral dissection, thrombosis, hypertension, renal infarction and rupture. IRAAs may be detected incidentally as well as present with urologic symptoms and signs related to complications. Actually, IRAAs are investigated by non invasive modalities including duplex ultrasound, magnetic resonance angiography, spiral three-dimensional computed tomography angiography, and three-dimensional reconstructed rotational digital substraction angiography of the segmental and distant branches of the renal artery. Angiography with intrarterial injection of contrast material is the gold standard in diagnosing IPRAAs. Treatment options for IPRAAs include observation, aneurysmectomy with surgical repair, endovascular procedures, nephrectomy or partial nephrectomy. Observation is indicated for asymptomatic intraparenchymal renal artery aneurysms measuring less than 2 cm in diameter. Surgical repair of IPRAAs includes aneurysmectomy and reconstruction of the renal artery by in vivo or ex vivo technique. The procedure is indicated for IPRAAs causing renovascular hypertension, dissection, urologic symptoms, embolization, local expansion and women of childbearing age with a potential for pregnancy. In recent years, transcatheter arterial embolization has emerged as a simple, useful and effective technique in managing IRAAs. The procedure is performed by transfemoral catheterization as well as by superselective catheterization and embolization of interlobar arteries with 3F microcatheters. Endovascular occlusion is obtained by using gelatin sponge, steel coils, detachable baloons, and conventional non-detachable microcoils delivered through a microcatheter. Nephrectomy or partial nephrectomy are reserved for conditions precluding renal revascularization which include overt RAA rupture, covert RAA rupture, artery-to-vein fistula, renal cell carcinoma, end stage nephropaty, renal infarction, severe ischemic renal atrophy or complex intrarenal aneurysms. Recently, partial nephrectomy by the laparoscopic approach has been proposed for managing IPRAAs and the procedure is considered feasible and safe.