[Trigeminal nerve dysfunction as a false localizing sign: a case of the choroid plexus papilloma in the IVth...

Trigeminal nerve dysfunction as a false localizing sign, although rate, is known to occur. A case of choroid plexus papilloma in the 4th ventricle with hemifacial numbness is presented. A 24-year-old woman had been suffering from intermittent facial numbness on the left side for 3 months prior to admission. She noted no other symptoms. Neurological examination disclosed marked papilledema, horizontal nystagmus on both lateral gazes and mild truncal ataxia. CT scans showed a calcified mass lesion in the 4th ventricle on the midline extending into the left lateral recess. It was enhanced homogeneously with contrast material. The pathogenesis of such a false localizing sign and its clinical implications were discussed from the anatomical point of view.