We describe the case of a 32-year-old man with generalized lymphadenopathy who was diagnosed with a low-grade follicular small-cleaved cell lymphoma. The patient developed hearing loss, tinnitus and cerebrospinal fluid (CSF) pleocytosis attributed to central nervous system (CNS) infiltration by his malignancy, while receiving chemotherapy with vincristine, cyclophosphamide and prednisone. Despite intrathecal chemotherapy with methotrexate, the CSF pleocytosis persisted. Neurosyphilis was suspected because of prior history of gonorrhea and was confirmed with serologic studies of blood and CSF and from the decline of the anti-treponemal antibody titers with appropriate antibiotic therapy. Syphilis should be considered in the differential diagnosis of patients with generalized lymphadenopathy and neurologic signs or symptoms.