- To characterize neurosarcoidosis of the trigeminal nerve clinically
& radiographically
- To assess its response to immunomodulatory treatments

Cranial neuropathies are amongst the most common manifestations of neurosarcoidosis. While many forms of cranial neuropathy are well-characterized in neurosarcoidosis, particularly facial and optic neuropathies, trigeminal neuropathy is not, despite being present in 5-13% of patients in reported cohorts

Patients with neurosarcoidosis were included if: 1) their sarcoidosis was pathologically-confirmed by biopsy, and 2) neuroimaging provided radiographic evidence for granulomatous inflammation involving the trigeminal nerve, its nucleus, or ganglion

Fourteen patients were included, representing 5.7% of the total neurosarcoidosis cohort, including 5 patients with symptomatic trigeminal neuropathy and 9 patients with asymptomatic radiographic trigeminal nerve involvement. Average age of neurosarcoidosis onset was 48.0 years, and most were African American (11/14, 78.6%) and male (8/14, 57.1%). All symptomatic patients presented chronically with unilateral symptoms (numbness in the trigeminal distribution in 5/14, 35.7%, and trigeminal neuralgia in 2/14, 14.3%), either in isolation (2/5, 40%) or as part of a greater constellation of neurologic symptoms (3/5, 60.0%). The most commonly affected trigeminal structures on contrasted MRI were the cisternal portion of the trigeminal nerve (9/14, 64.3%), Meckel’s cave (7/14, 50.0%), and the cavernous sinus (5/14, 35.7%). At least one routine CSF parameter was abnormal in 10/12 (83.3%) tested patients. Four symptomatic patients were treated with corticosteroids, with 3/4 (75.0%) experiencing complete resolution or partial symptomatic improvement. Twelve patients had follow-up MRIs after receiving treatment with trigeminal inflammation completely resolving in 9/12 (75.0%) and partially improving in 3/12 (25.0%). The average last mRS was 1.4 after an average follow-up period of 91.5 months. 

Neurosarcoidosis more commonly affects the trigeminal nerve radiographically than clinically, and symptomatic patients may experience anesthesia dolorosa in the trigeminal distribution. This form of neurosarcoidosis responds very well to treatment, both clinically and radiographically.