Growth and spontaneous regression of a middle cerebral artery aneurysm after surgical clipping

We present a case of growth and spontaneous regression of a middle cerebral artery aneurysm after surgical clipping. A 36-year-old woman who presented with grade II subarachnoid haemorrhage was found to have a right middle cerebral artery aneurysm. The aneurysm was surgically clipped in view of the morphology of the aneurysm. Second clipping was performed four months later as there was re-growth of the neck of the aneurysm. Again re-growth of the aneurysm was noted five months after the second clipping. As further clipping of the aneurysm would be difficult, external and internal carotid arteries bypass was the treatment option but unfortunately, the by-pass operation was unsuccessful. Interestingly, angiogram performed after the bypass surgery revealed partial thrombosis and decreasing size of the aneurysm. Complete obliteration of the aneurysm was noted without further intervention one month after the failed by-pass surgery.