Intracranial Aneurysms in Patients with nf2-related Schwannomatosis: Illustrative Case and Review of the Literature

Introduction: NF2-Related Schwannomatosis (NF2), previously known as neurofibromatosis type 2, is an autosomal dominant disorder characterized by bilateral vestibular schwannomas (VS) and other central nervous system neoplasms. Although there is evidence linking intracranial aneurysms and neurofibromatosis type 1 (NF1), such an association has yet to be established in NF2. Therefore, this study aims to elucidate the potential association between NF2 and intracranial aneurysms.

Methods: The case of a 22-year-old NF2 patient presenting with a ruptured anterior inferior cerebellar artery (AICA) aneurysm is described. A literature review of intracranial aneurysms in patients with NF2 was also conducted within the PubMed, Embase, and MEDLINE databases.

Results: Six studies, comprising 11 patients with a total of 17 aneurysms, were identified. When including the present case, the total is brought to 12 patients (n=12) with 18 aneurysms. The average age at aneurysm identification was 28.3 ± 10.3 years (mean=28.3, SD=10.3). Aneurysms were incidentally found in 58% of patients (n=7), of which 57% (n=4) were managed with routine monitoring via angiography or MRA, 14% (n=1) treated with microsurgical clipping, and 29% (n=2) treated endovascularly. In 41.7% (n=5) of patients, aneurysms were first discovered at the time of presentation for subarachnoid hemorrhage. 40% (n=2) of these patients did not survive the rupture. All 7 patients with unruptured aneurysms remained asymptomatic. The patient treated by the authors suffered no operative complications and was discharged at their neurologic baseline.

Conclusion : Despite routine radiographic monitoring, a considerable proportion of NF2 patients present with rupture as the first sign of intracranial aneurysm. This finding, coupled with the high rupture mortality rate, suggests that current screening guidelines for CNS tumors in NF2 patients might not adequately encompass this population’s risk for intracranial aneurysms. Further investigation is needed to quantify this risk so that an evidence-based aneurysm screening protocol can be developed.