[A case of neurosyphilis presenting as bilateral temporal, cortical and subcortical encephalitis].

A 37-year-old man who had a low grade fever for 5 days admitted to our hospital due to disturbance of consciousness and seizure. Brain MRI showed abnormal hyperintensity in the bilateral temporal lobes, cortical and subcortical lesions on fluid-attenuated inversion recovery image. Treponemal and non-treponemal specific antibodies were positive in serum and cerebrospinal fluid, therefore he was diagnosed as having neurosyphilis. Treatment with intravenous penicillin G and metylpredonisolone improved his clinical symptons, imaging abnormalities and CSF findings. Patients of neurosyphilis with mesiotemporal encephalitis show common features such as young age, HIV-negative, subacute cognitive impairment and seizure, as seen in our case. Early diagnosis of neurosyphilis and appropriate treatment make clinical improvement, however the clinical diagnosis of neurosyphilis is sometime difficult because most patients present with disturbance of consciousness or seizure. The possibility of neurosyphilis should be considered when MRI results indicate temporal abnormalities.