A 63-year-old man presented to the Emergency Department with the complaints of pain and swelling of the right lower extremity. The history included intermittent pain and swelling of the right leg for about 1 year that had become prominent and intractable in the last day. At the time of admission the patient was conscious and cooperative. The vital signs were normal. Physical examination revealed diffuse edema of the entire right leg with a positive Homan’s sign. Peripheral arterial pulses of the right leg distal to the popliteal artery were faint on palpation. Respiratory system examination was unremarkable. The abdomen was not tender, bowel sounds were normal, guarding or rebound was not present. Abdominal palpation was suspicious for a pelvic mass. The patient was evaluated by color Doppler sonography examination that revealed thrombosis of the deep veins of the right lower extremity and also in the right common and external iliac veins. A mass 10 cm in diameter was noted in the pelvic cavity adjacent to the right common iliac vein. Color encoding demonstrated that the right common iliac artery was displaced anteriorly and the mass was contiguous to the artery. The mass was presumed to be a thrombosed iliac artery aneurysm. On computed tomography (CT) scan, the arteries were shown to have a tortuous course with thrombosis of the veins from the right iliac to the femoral vein (Figure 1). The mass that was detected by color Doppler sonography was shown to be an aneurysm of the right common iliac artery, originating from the portion just distal to the iliac artery bifurcation (Figure 1, Figure 2). The aneurysm developed from the posterior aspect of the common iliac artery, fusiformly grew distally with its partially thrombosed lumen, and became a huge space-occupying mass in the pelvic cavity (Figure 2A). The right iliac vein was laterally displaced by the aneurysm and the distal venous system was thrombosed by its mass effect (Figure 2B). The patient underwent an operation in which the aneurysm was extirpated, an ilio-femoral bypass graft was implanted, and femoral vein thrombectomy was performed.
Figure 1. A,B) Contrast enhanced CT images just below the level of iliac bifurcation demonstrating the aneurysm (long arrows) originating from the posterior aspect of the right common iliac artery. Note the tortuous course of the left common iliac artery (short arrows).
Figure 2. A) The aneurysm (arrows) occupies most of the midline and the right side of the pelvic cavity. A great area of the aneurysmal cavity has thrombosis inside. The patent lumen is indicated by a short arrow. B) The image caudal to the aneurysm showing the thrombosis of the external iliac vein (arrow).
Deep venous thrombosis (DVT) results mainly from three factors: the slowing down or obstruction of the blood stream secondary to an injury to the veins, or due to the hypercoagulability states. External compression is one of the major causes of DVT, however, isolated iliac artery aneurysm is an uncommon mass that may cause lower extremity DVT. Apart from the compressive effect in the pelvic cavity, iliac artery aneurysms also have some important potential risks. The rupture of the aneurysm and development of an arteriovenous fistula are the major possible complications that are catastrophic clinical events 1, 2. Inappropriate treatment of patients with venous obstruction from unrecognized arterial aneurysms has been reported to be associated with great mortality and morbidity (1). The elimination of hazardous risks may be provided by accurate diagnosis and timely aneurysm repair, as in the presented case.
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