Pituitary Adenomas Associated with Intracranial Aneurysms: The Clinical Characteristics, Therapeutic Strategies, and Possible Effects of Vascular Remodeling Factors

Background Pituitary adenoma coexists with intracranial aneurysms in 2.3 to 3.6% of cases, and intracranial aneurysms are thought to be incidental. On the other hand, older age and cavernous sinus invasion are reported to increase the rate of coexistence, so these two diseases may be related. Methods Ten males and 14 females with the coexistence of pituitary adenomas and intracranial aneurysms were retrospectively investigated among 923 patients (2.6%). Patients were subdivided into two groups: those with direct attachment of cerebral aneurysms to the pituitary adenomas and those without direct attachment. The clinical characteristics, therapeutic strategies, and possible effects of vascular remodeling factors were investigated. Results Twelve patients had functioning pituitary adenomas, and cavernous sinus invasion was identified in 7 of 24 patients. Five of these 7 patients were treated with priority for the cerebral aneurysm until 2007, whereas 14 of 17 patients without involvement of the aneurysm tip in the tumor were treated with priority for the pituitary adenoma in the later period. Among vascular remodeling factors, strong expression of vascular endothelial growth factor (VEGF) was significantly associated with the coexistence of pituitary adenoma and cerebral aneurysm (p < 0.05). Conclusion Intracranial aneurysms were found to coexist in 2.6% of cases of surgically treated pituitary adenomas. VEGF-induced arterial wall remodeling may be part of the mechanism of association between pituitary adenomas and cerebral aneurysms, suggesting possible causative mechanism.