Development and spontaneous regression of a de novo posterior communicating artery aneurysm in a child following gamma knife stereotactic radiosurgical obliteration of a cerebral AVM: Case report and review of the literature
Tristram G. Horton, Peter H. Ma and Kevin M. Cockroft
Reports of the development of true intracranial aneurysms after radiosurgery are exceedingly rare and unconvincing. We report the case of a young boy who developed a posterior communicating artery aneurysm after the Gamma Knife radiosurgical treatment of a thalamic AVM. This ten year-old presented with left upper extremity tremors. MRI/MRA revealed a right thalamic AVM. No intracranial aneurysms were found on initial angiography. The patient underwent two-stage endovascular embolization of his AVM followed by Gamma Knife radiosurgical treatment (18 Gy delivered to the 50% isodose line). Follow up angiogram at 38 months confirmed obliteration of the AVM, but revealed a new 2.2 x 1.5 mm aneurysm located at the origin of the right posterior communicating artery. A MRA obtained 5 months later (43 months after treatment) demonstrated regression of the aneurysm. This is the first report of the development of an intracranial aneurysm after Gamma Knife radiosurgery in a child and the first description to include pre and post-treatment angiography that clearly demonstrates interval aneurysm development. Although the aneurysm showed subsequent regression during continued follow-up, this report illustrates the critical importance of post-treatment angiography for patients with intracranial AVM treated in this manner.
Keywords: Aneurysm, cerebral; arteriovenous malformation, brain; Gamma Knife; radiosurgery; angiography; neuroimaging; magnetic resonance imaging