Presentation
Left retro-orbital headache associated with left eye watering and left nostril rhinorrhea.
Patient Data
Contrast enhanced CT shows a low density lesion within the left carotid canal which appears extrinsic to the ICA (located anterior and inferior to the vessel which is not narrowed). There is subtle expansion of the canal relative to the right, and smooth bone remodeling.
MRI reveals a T2 hyperintense, T1 isointense, enhancing mass within the left carotid canal and extending partially into the left cavernous sinus. It extends a short distance into the neck below the carotid canal.
Case Discussion
Although extremely rare, sympathetic schwannoma of the carotid canal is the likely diagnosis in this case. The signal characteristics and smooth bone remodeling are in keeping with schwannoma. Internal carotid artery dissection would be a far more common pathology to involve the carotid canal however the appearance in this case is clearly of an extrinsic mass and not dissection.