Interval growth in an ICA bifurcation aneurysm treated with balloon occlusion, and possible contribution of vasa vasorum hypertrophy

We present a rare case of an ICA aneurysm recurrence despite treatment with ICA balloon occlusion. There was evidence of ICA recanalization bypassing the balloons on a catheter angiogram follow-up 1 year post-procedure. Although initially stable in size, at 5 years after the original procedure, the aneurysm demonstrated evidence of enlargement and on angiography there was further enlargement of the recanalized ICA around the occluding balloons. We postulate that this has been caused by increasing antegrade flow through hypertrophied vasa vasorum in response to persistently increased demand for blood flow by the ipsilateral hemisphere; this indirectly may have also contributed to some extent to the aneurysm enlargement.