A 39-year-old man with kidney failure from IgA nephropathy was referred to our hospital for kidney transplantation. He was taking warfarin for 2 previous episodes of pulmonary embolism. To investigate the possible cause of the pulmonary embolisms, he underwent a hypercoagulable workup, which was negative, and no deep vein thrombi were noted in his lower extremities on ultrasonography. Computed tomography (CT) displayed a homogeneous isodensity lesion in the peribladder region (Supplementary Figure S1). Further investigation by 3-dimensional computed tomography angiography demonstrated this lesion to be a large aneurysm located near the bladder in the pelvis, which was connected to both internal iliac arteries, suggesting arteriovenous malformation (AVM) (Figure 1). Three-dimensional reconstruction of selective pelvic angiography displayed high-flow AVM with feeding arteries from both internal iliac arteries and multiple engorged veins (Figure 2; Supplementary Figure S2), and the diagnosis of congenital pelvic AVM was confirmed. The patient’s previous history of pulmonary embolism could therefore be explained by the AVM.

Figure 1Three-dimensional computed tomography angiography. Three-dimensional computed tomography angiography displaying arteriovenous malformation originating from both internal iliac arteries. Dilated and tortuous drainage veins were displayed in the pelvis (arrows). White bar = 5 cm.

Figure 2Three-dimensional reconstruction angiography. Three-dimensional reconstruction of selective right internal iliac angiography displaying a large pelvic arteriovenous malformation consisting of multiple feeding vessels arising from the right internal iliac artery. White bar = 5 cm.