A 60-year-old woman presented with 1-week history of painless left monocular vision-loss. Neurological exam showed APD and hand-motion visual-acuity on the left.  ESR (77mm/hr) and CRP (12.1mg/L) were elevated. Serum ACE was weakly positive (88U/L).  MRI brain with-and-without contrast revealed enhancement in the left optic nerve along with an abnormal T2-signal in the right lateral temporal lobe extending into the cortex with enhancement. CTA head exhibited diffuse luminal arterial irregularity, most pronounced distally, indicative of vasculitis. Lumbar puncture was notable for lymphocytic pleocytosis (WBC 46/cmm, 73% lymphocytic), elevated protein (66mg/dL), and normal glucose (59mg/dL). CT chest revealed extensive bilateral mediastinal and hilar adenopathy. Endobronchial biopsy was negative for malignancy or granulomatous changes. Left temporal-artery biopsy was performed and negative for giant cell arteritis(GCA). Patient was treated with 1g methylprednisolone daily for three-days with noticeable improvement in vision enabling finger-counting. She was then started on Prednisone 60mg daily with differential of GCA or neurosarcoidosis. Subsequent excisional biopsy of the right-paratracheal lymph nodes revealed non-caseating granulomatous lymphadenitis. Assessment of visual acuity one month after initiation of steroids revealed further improvement (20/150) in left-sided vision.

Here, we present a unique case of neurosarcoidosis presenting with optic neuritis and cerebral vasculitis. Initial presentation with temporal headache was concerning for GCA. Temporal artery biopsy was negative which is not uncommon. Work up was continued with eventual diagnosis made with a lymph node biopsy showing non-caseating granulomas. This case highlights the importance of recognizing sarcoidosis in the differentials when assessing a patient with optic neuritis or vasculitis.