Title : Intracranial Mass: Meningioma vs. Thrombosed Aneurysm
Correct identification and analysis of intracranial masses is of high clinical importance especially when it comes to treating acute illnesses and focal neurological deficits, while preventing further deterioration.
We present a rare case of a giant thrombosed aneurysm in the intracavernous segment of the right internal carotid artery (ICA). The patient, a 75-year-old female, presented with nine months of progressive headache, right cranial nerve III palsy, and retroorbital pain with no significant past medical history. The initial CT (computed tomography) scan of the brain revealed a suprasellar and right periclinoid calcified mass, forming an initial suspicion for a meningioma. Further imaging consisted of a CT angiogram of the head and neck, which showed occlusion in the cervical and clinoid region of the right ICA with preserved right ACA (anterior cerebral artery) and MCA (middle cerebral artery) blood flow via collateral circulation.
Following a neurosurgery consult for the diagnosis of a meningioma, the patient was placed on Lovenox for DVT (deep vein thrombosis) prophylaxis. A subsequent IR (interventional radiologic) cerebral angiogram obtained four days later revealed recanalization of the previously occluded right ICA with a large dissecting aneurysm in the petrous/cavernous segment. This revelation immediately redirected the treatment plan for this patient, as neurosurgeons were now dealing with an aneurysm as opposed to a meningioma.
This case describes a perplexing situation that led many physicians to believe this was a meningioma, based on radiographic findings. However, administration of Lovenox led to a completely different diagnosis. The aneurysm was previously completely thrombosed and angiographically occult in the initial CT scan, leading to the diagnosis of a meningioma. When the patient received Lovenox, this caused the aneurysm to rebleed and the patient to become symptomatic. The CTA confirmed this as the aneurysm had recanalized as a result. Therefore, administering Lovenox can drastically change the features of an angiographically occult thrombosed aneurysm and yield diagnostically significant clues on the genesis of focal neurological deficits.
Premature resection of a suspected meningioma prior to further radiographic investigation would have put the patient at risk for perioperative aneurysm rupture, resulting in massive intracranial hemorrhage and other life-threatening complications. The aneurysm was ultimately treated with pipeline flow diverter embolization (PFDE) and the patient is clinically stable as of today. This case reflects the critical importance of considering differential diagnoses when a sphenoid mass is discovered and it does not appear to homogeneously enhance as a typical meningioma would.
What will audience learn from your presentation?
- This will assist healthcare professionals that are faced with similar presentations in expanding their differential diagnoses for intracranial masses.
- Radiographic identification of intracranial masses and understanding that aneurysms may appear differently when thrombosed vs. when it is recanalized and blood flow is restored
- Keeping in mind the consequences of operating on intracranial masses that my result in active bleeding
- Understanding the consequences of using anticoagulants and how it can change interpretation of intracranial radiographic findings
- Utility of the pipeline diverter flow embolization device in the treatment of intracranial aneurysms