Cryptogenic oculomotor nerve palsy. The need for repeated neuroimaging studies

Five children between ages 3 and 17 years developed slowly progressive oculomotor nerve palsies. No cause was found on initial clinical or neuroradiologic investigations. Subsequent computed tomography or 1.5-T magnetic resonance imaging revealed a mass along the course of the involved oculomotor nerve in three of the five cases. The clinical and radiologic characteristics of these tumors are consistent with the diagnosis of schwannoma or, less likely, meningioma. Children with acquired oculomotor nerve palsies of initially unknown etiology should undergo imaging every two years with the expectation of eventually detecting a small tumor somewhere along the course of the oculomotor nerve.