A Giant Internal Carotid Bifurcation Aneurysm as a Rare and Dangerous Differential Diagnosis of a Craniopharyngioma.

Craniopharyngiomas are supra/parasellar lesions that often present with general, unspecific symptoms. Similarly, internal carotid artery (ICA) bifurcation giant aneurysms may also produce calcified, heterogeneous, parasellar expansive lesions, posing a relevant differential diagnosis due to their inherently different surgical strategies and risks. We report the case of a 54-year-old female presenting with progressive disorientation and apathetic behavior. CT and MRI reports described a suprasellar heterogenous mass with calcifications associated with an adjacent, laterally located fluid collection suggestive of a craniopharyngioma. During the surgical procedure, perfuse and unexplained arterial bleeding ensued, prompting the surgical team to review a previous contrast-enhanced CT scan. Careful inspection revealed an image suggestive of vascular pathology, with an area of continuous hyperdensity along the right ICA bifurcation. The Sylvian fissure was dissected, and an aneurysmal neck was encountered and successfully clipped. Giant intracranial aneurysms are rare but essential differential diagnoses to be considered during the workup and surgical approach toward parasellar mass lesions. This case illustrates the importance of performing a CT angiogram (CTA) for skull base lesions, even when the size is more suggestive of tumor pathology.