CT and MRI findings of sphenoid sinus internal carotid artery pseudoaneurysm: an important and challenging differential diagnosis for a skull base mass.

Intrasphenoid internal carotid artery (ICA) pseudoaneurysm can present as and mimic a sinonasal mass. The purpose of this review is to describe the computed tomography (CT) and magnetic resonance imaging (MRI) features that should prompt the radiologist to consider this lesion in the differential diagnosis of a skull base mass. Specifically, when a sphenoid mass appears hyperdense, expansile, and destructive on CT and has mixed T1 signal and/or flow-related artefacts on MRI, the differential diagnosis should include a pseudoaneurysm. Vascular imaging is warranted to confirm the diagnosis.