Ocular syphilis masquerading as optic neuritis in a human immunodeficiency virus-positive patient: A diagnostic challenge

Syphilis, known as “the great imitator,” can present with a wide spectrum of ocular manifestations, including optic neuritis, uveitis, and chorioretinitis, often complicating diagnosis, particularly in human immunodeficiency virus (HIV)-infected individuals. We report a case of a 52-year-old HIV-positive, diabetic man who presented with painless vision loss initially misdiagnosed as optic neuritis. Fundoscopy and optical coherence tomography (OCT) revealed optic disc edema, subretinal fluid, and ellipsoid zone disruption. Further history uncovered a recent genital ulcer, and serologic testing confirmed syphilis despite a negative Venereal disease research laboratory (VDRL). The patient received intravenous penicillin G, leading to significant visual recovery and resolution of ocular findings. This case underscores the importance of considering syphilis in atypical or treatment-resistant optic neuropathies, especially in the context of HIV co-infection, and highlights the need for comprehensive serologic testing for timely diagnosis and treatment to prevent irreversible visual impairment.