Introduction: We report two cases with a new subtype renal arteriovenous malformation (AVM) and describe their angioarchitecture and endovascular therapy.

Case Series: In a 31-year-old postpartum patient with a sudden onset of hemorrhagic shock, CT showed a large renal arterial aneurysm and a retroperitoneal hematoma. Pre-embolization angiography showed that the left middle adrenal artery had a cirsoid AVM with a fistula to a large saccular aneurysm arising from the left main renal artery. Her vital sign was stable after a complete occlusion of the cirsoid arteries by the deployments of microcoils. But coil packing of the aneurysm was limited to partial because too many detachable coils were needed. Finally, a partial aneurysmectomy of the residual lesion was performed. A 79-year-old man who had undergone chronic hemodialysis had a right renal aneurysm, 4 cm in diameter, which was diagnosed as a venous aneurysm in a dilated draining vein of cirsoid type AVM Coil embolization of the main renal artery and the segmental artery feeding the AVM was performed resulting no visualization of the aneurysm on angiography. However, follow-up CT showed residual flow in the aneurysm.

Conclusion: Both diagnostic and interventional radiologists should pay an attention to a new subtype of renal cirsoid AVM which is combined with aneurysm.

Keywords: Aneurysm, Arteriovenous malformation, Embolization, Kidney