Neurosyphilis has become uncommun in the developed countries.We report a case of neurosyphilis with limbic presentation, left mesiotemporal lesions on MRI and severe anterograde amnesia.Pathogeneses of MRI findings are unknown. We suggest the implication of arteritis wich affects small vessels, parenchymatous and excitotoxic lesions. The absence of mesiotemporal lesion in immunodeficient patients, the limbic systematization of pathology underlines the involvement of probably auto-immune process. Neurosyphilis should always be considered in the differential diagnosis of limbic encephalitis in order to initiate treatment and to prevent cognitives sequelaes. At last, partial status epilepticus should be diagnosed and excitotoxicity lesions prevents with antiepileptic treatment.
