GIANT INTRACRANIAL ANEURYSMS WITH SKULL BASE EROSION AND EXTRACRANIALMASSES - CT AND MR FINDINGS

Objective: To present the CT and MR findings of three patients with gi ant intracranial aneurysms (GIAs), each of which eroded the skull base and had an extracranial mass component. A literature review of GIAs w as also performed. Materials and Methods: In the past year the imaging studies of three patients with these unusual GIAs were collected at o ur institutions. All three patients had had CT, and one patient had ha d MR on a 1.5 T GE unit. Results: One patient had a 5 cm GIA in the le ft petrocavernous region, filling the middle cranial fossa and extendi ng into the left sphenoid sinus and the left posterior ethmoid complex . The aneurysm had heterogeneous high attenuation and extensive rim ca lcification. The second patient had a 5 cm GIA that filled most of the left middle cranial fossa, eroding the floor and lateral wall and ext ending into the infratemporal fossa and parapharyngeal space. The aneu rysm was partially thrombosed and had minimal rim calcification. The t hird patient had a 4 cm left cavernous GIA that eroded the floor of th e middle cranial fossa and extended into the subjacent parapharyngeal space. The lesion was partially thrombosed and had an enhancing lumen. The rim had low signal intensity on MR. None of these patients had a history of trauma. Conclusion: Giant intracranial aneurysms can cause significant skull base erosion and extend into the paranasal sinuses, parapharyngeal space, and infratemporal fossa. The CT and MR findings can lead to an accurate diagnosis.