[Tuberous sclerosis and intracranial aneurysms: a rare association]

Intracranial aneurysms in patients with tuberous sclerosis complex: a systematic review

OBJECTIVE

Tuberous sclerosis complex (TSC) is a rare multisystem genetic disease. Arterial wall developmental disorders, such as aneurysms, in association with TSC have been well described for extracranial vasculature. The characteristics of intracranial aneurysms (IAs) in TSC have not previously been addressed in the literature. This systematic review was performed to identify and assess the distinct characteristics of IAs in patients with TSC.

METHODS

The authors searched PubMed, Scopus, and Web of Science for publications describing cases of TSC and IA reported before August 7, 2018. They also report 2 cases of IAs in TSC patients treated at their own institution.

RESULTS

Thirty-three TSC patients with a total of 42 IAs were included in this review. Three individuals presented with subarachnoid hemorrhage. The IAs were large or giant in 57.1% and fusiform in 45.2% of the cases. Most of the IAs (61.9%, 26 of 42) originated from the internal carotid artery. There was a higher prevalence of pediatric cases (66.7%) and male patients (63.6%, 21 of 32 individuals with known sex) among the collected series.

CONCLUSIONS

TSC patients with IAs are characterized with a higher proportion of large/giant and fusiform IAs and young age, suggesting rapid aneurysmal growth. Furthermore, there is a distinct location pattern of IAs and an inverse sex ratio than in the healthy population. Large population-based patient registers are required to improve the understanding of epidemiology and pathophysiology of IA formation in TSC.

Factors affecting formation and rupture of intracranial saccular aneurysms

Unruptured intracranial aneurysms represent a decisional challenge. Treatment risks have to be balanced against an unknown probability of rupture. A better understanding of the physiopathology is the basis for a better prediction of the natural history of an individual patient. Knowledge about the possible determining factors arises from a careful comparison between ruptured versus unruptured aneurysms and from the prospective observation and analysis of unbiased series with untreated, unruptured aneurysms. The key point is the correct identification of the determining variables for the fate of a specific aneurysm in a given individual. Thus, the increased knowledge of mechanisms of formation and eventual rupture of aneurysms should provide significant clues to the identification of rupture-prone aneurysms. Factors like structural vessel wall defects, local hemodynamic stress determined also by peculiar geometric configurations, and inflammation as trigger of a wall remodeling are crucial. In this sense the study of genetic modifiers of inflammatory responses together with the computational study of the vessel tree might contribute to identify aneurysms prone to rupture. The aim of this article is to underline the value of a unifying hypothesis that merges the role of geometry, with that of hemodynamics and of genetics as concerns vessel wall structure and inflammatory pathways.