Neurosarcoidosis presenting as mononeuritis multiplex.

Sarcoidosis is a multisystem granulomatous disease of unknown etiology, with prevalence ranging from 1 to 50 per 100,000. Neurologic involvement occurs in up to 5% of patients but can be the initial presentation of sarcoidosis in 50% of those affected by neurosarcoidosis. The authors report a case of mononeuritis multiplex of the ulnar and then the radial nerve that subsequently led to a diagnosis of sarcoidosis in a patient 8 mos after initial presentation. It is important that neurosarcoidosis be in the differential diagnosis of mononeuritis multiplex when other causes cannot be found because early treatment could help prevent progression to other nerves.