Case Report of Internal Carotid Artery Aneurysm and Pituitary Adenoma: Causal or by Chance Relationship?

Background: Unruptured Intracranial aneurysms have the prevalence of 3% in the general population. Pituitary adenomas, meningioma and gliomas have been associated with higher prevalence of aneurysm formation. they hypothesized a causal relationship either resulting from the changes related to the hormone production, or by mechanical compression. In this case the ICA aneurysm has occurred twelve years before a pituitary adenoma has been diagnosed. This question the casual relationship between the ICA aneurysm and the pituitary adenoma.

Case Presentation: A 64-year-old women presented to the clinic with a headache and blurred vision. She has a family history of aneurysm formation in her brother. She underwent a left frontotemporal craniotomy for ICA aneurysm clipping 12 years earlier. During the follow up period, the patient complained of blurry vision and headache that drew attention to undergo further investigations. Ophthalmologic evaluation revealed a bitemporal superior quadrant hemianopsia. The fact that the patient had two Sugita aneurysm clips no.37 and no.33, MRI brain could not be obtained. Initial CT non contrast images (Fig. 1 A, B) showed a slightly enhancing lesion in the sellar and suprasellar region. Conventional angiography (Fig. 1 C, D) that showed a normal flow in the left ICA with evidence of two aneurysm clips in the left supra-clinoid region in close proximity to the posterior communicating artery. No residual or recurrent aneurysm was detected elsewhere. The patient was planned to undergo an endoscopic endonasal surgery with the use of intraoperative image guidance. The tip of the aneurysm clip (Fig. 2) was noted close to this area and the tumor was dissected from around the clip. Last portion of the tumor extending posteriorly on the top of the dorsum sellae was removed. The patient tolerated surgery well with no postoperative complications. Follow up CT scan (Fig. 1 E, F) after surgery showed no residual tumors. No recurrence was encountered in 8 year follow up period. She is neurologically intact with no need for hormonal replacement.

Conclusion: The association between the ICA aneurysm and pituitary adenoma has been discussed in the literature. Though previous theories explained this as a hormonal or mechanical effect on surrounding vasculature that cause the aneurysm. This case showed the reverse. This question the causal relationship of such association. Surgeons should be aware of this possible association to avoid complications.

Fig. 1 CT scans sagittal (A) and coronal (B) sections showing hyperdense sellar lesions in close proximity to an aneurysm clip. DSA coronal (C) and sagittal (D) showing no residual or recurrence of previously clipped aneurysm. Postoperative CT scans sagittal (E) and coronal (F) sections showing gross total resection of the tumor with no residuals.

Fig. 2 Intraoperative endoscopic view of the tip of the aneurysm (arrow) clip encroaching on the sellar space.