54-year-old man with hypertension, chronic migraines and NHL (Follicular lymphoma s/p 6 sessions of chemotherapy) admitted for chronic meningitis manifested by subacute headaches, left cranial nerve (CN) 6 palsy and gait instability. Brain MRI revealed leptomeningeal enhancement involving multiple CN’s and whole spine MRI showed enhancement of the conus and cauda equina. CSF studies showed elevated white cells of 94 (78% lymphocytes), high total protein (516), low glucose (24) and negative cytology so leptomeningeal carcinomatosis from a CNS relapse of NHL was suspected. CSF flow cytometry later showed 60% lymphocytes (predominantly T cells), fewer NK cells and absent B cells which does not correlate with B cell lymphoma. Further investigation showed that patient had a typical syphilitic body rash (including palms) with skin biopsy revealing treponemal organisms, and positive serology (RPR 1:2, reactive serum/CSF fluorescent treponemal antibodies). Patient was diagnosed with neurosyphilis and started on IV penicillin 24 million units daily, with significant clinical improvement and discharged home with 14 days of IV Penicillin .