Neurosarcoidosis of the trigeminal nerve: clinical accompaniments, radiographic findings, and association with neuralgia.

BACKGROUND: Cranial neuropathy is a principal disease manifestation of neurosarcoidosis, but many forms remain poorly described, including trigeminal nerve disease despite its frequency in reported cohorts (5-12%). Herein, we characterize the clinical course of patients with neurosarcoidosis involving the trigeminal nerve. METHODS: A single-center retrospective cohort analysis of patients with biopsy-proven sarcoidosis involving the trigeminal nerve was conducted between 1/1/2000-3/7/2023. RESULTS: The trigeminal nerve was affected in 14/245 (5.7%) patients, being clinically symptomatic in 5/245 (2.0%) and asymptomatic with radiographic involvement in 9/245 (3.7%). 14/14 (100.0%) patients had systemic sarcoidosis. In the symptomatic group, trigeminal neuropathy was an inaugural feature in 4/5 (80.0%), unilateral in 5/5 (100.0%) with the V1 subdivision most affected (4/5, 80.0%), and associated with neuralgia in 2/5 (40.0%). On MRI, the cisternal nerve roots (9/14, 64.3%), Meckel's cave (7/14, 50.0%), and cavernous sinus (5/14, 35.7%) were most commonly affected, and 14/14 (100.0%) patients had extra-trigeminal neuroinflammation on cranial MRI. CSF was abnormal in at least one dimension in 11/12 (91.7%) tested. All three treated patients with symptomatic trigeminal neuropathy responded to immunomodulatory treatment, and symptomatic treatments for trigeminal neuralgia were helpful in two patients. After a median follow-up period of 63 months, the median modified Rankin scale score was 1 for both subgroups. CONCLUSION: Neurosarcoidosis may involve any portion of the trigeminal apparatus, and when affected, it frequently demonstrates a mismatch in radiographic involvement from its clinical manifestations of facial numbness and pain, and typically occurs in association with other clinical or radiographic manifestations of neurosarcoidosis.