A 27-year-old male presented with Left eye pain, ptosis, ophthalmoplegia, facial paresthesias, and unrelenting severe headaches. He was previously seen and treated for meningoencephalitis after neuroimaging revealed right frontal dural enhancement, but was discharged after a negative infectious workup. Symptoms progressed with examination now revealing complete cranial nerve III, IV, V1, V2, and VI palsies.
MRI/MRA/MRV revealed pachymeningeal enhancement and thickening of the left middle fossa, cavernous sinus, tentorium, and orbital apex, but no vascular abnormalities. CT chest/abdomen/pelvis revealed an indeterminate renal lobulation, Ophthalmologic exam was normal, and CSF studies were benign. A left middle cranial fossa biopsy later revealed aggregates of inflammatory histiocytes, T-cells, plasma and B-cells clustered around nerves and inside endoneurium. ACE levels later returned normal.