A case of cavernous sinus syndrome following a mycotic aneurysm of extracranial carotid artery

: A 66-year-old man was admitted to our department with left abducens palsy and pain in the territory of the left trigeminal nerve. He had a history of left mandibular osteomyelitis that had been treated for five years in the dental department. However, the osteomyelitis was resistant to therapy. Two months before this admission, he had an infectious aneurysm of the left extracranial carotid artery with occlusion. On admission, the ESR was 140 mm/hour. P-ANCA and antinuclear antibody were negative. Lumbar puncture revealed elevated cell counts (43% neutrophils) and protein. Microbiological studies were negative. Cranial MR images showed an enhanced lesion in the left cavernous sinus. His condition gradually improved with high dose of penicillin and low dose of corticosteroid. However, he died of pulmonary embolism after 81 days. At autopsy, the left extracranial carotid aneurysm was highly fibrose. The left CCA, ICA, and ECA were occluded from the origin of the left common carotid artery to the ICA in the cavernous sinus. There were also fibrosis, hemosiderin, and macrophages around these arteries, and parts of these arteries were destroyed. The left cavernous sinus lesion was also highly fibrose. These pathological findings indicated that there was old inflammation around the left extracranial carotid aneurysm, left carotid artery, and left cavernous sinus. We believe that the left cavernous sinus syndrome in our patient was caused by left carotid artery vasculitis induced by the left infectious extracranial carotid aneurysm. We also believe that this infectious aneurysm was caused by the left mandibular osteomyelitis.