Infectious aneurysm of the intracavernous carotid artery occurring concomitantly with sphenoid sinusitis; an autopsy case report

A previously healthy 56-year-old woman presented with right-sided ophthalmic pain and diplopia following headache and fever. A neurological examination revealed 3rd and 6th right cranial nerve palsies. Brain magnetic resonance imaging (MRI) and 3D-computed tomography (CT) angiography (CTA) showed right-sided sphenoid sinusitis, cavernous sinus thrombophlebitis, and aneurysms in the right intracavernous carotid artery and in a portion of internal carotid-posterior communicating artery. We diagnosed her condition as cavernous sinus syndrome with an infectious aneurysm secondary to sphenoiditis; therefore, broad spectrum antibiotics were administered. However, 7 days after admission, she died of massive epistaxis. Macroscopically, coagulated blood was observed at the surface of the sphenoid sinus, suggesting bleeding in the cavernous sinus. A histopathological examination revealed severe infiltration of the inflammatory cells into the cavernous sinus and sphenoid mucosa. Rupture of the aneurysm in the cavernous sinus was also observed. However, no pathogenic organism was identified. We thought that the sphenoid sinusitis had spread through the venous flow into the cavernous, and the infectious aneurysm developed due to infiltration of inflammatory cells into the arterial wall. This is the first detailed clinico-pathological study of an infectious aneurysm in the intracavernous internal carotid artery occurring concomitantly with sphenoiditis.