Clinical and multimodal imaging features of ocular syphilis with posterior segment involvement: a 10-case series.

Abstract

Background: Ocular syphilis masquerades as posterior uveitis, causing delayed diagnosis. We delineated phenotypes, imaging and outcomes in treatment-naïve disease.

Methods: A retrospective, observational case series was conducted on 10 consecutive patients (15 eyes; 6 females, 4 males; mean age 48.3 ± 12.1 years) diagnosed with syphilitic posterior uveitis between January 2013 and December 2024. All patients underwent comprehensive ophthalmic evaluation, serologic confirmation (positive Treponema pallidum particle agglutination and rapid plasma reagin), and multimodal imaging assessment including color fundus photography, fundus fluorescein angiography (FFA), and spectral-domain optical coherence tomography (SD-OCT). The primary outcome was the change in best-corrected visual acuity (BCVA, logMAR) after standard intravenous penicillin G therapy, analyzed using the Wilcoxon signed-rank test.

Results: (1) Phenotype distribution: ASPPC was the most prevalent posterior-segment lesion (8/15 eyes, 53.3%), followed by optic perineuritis/papillitis (5 eyes, 33.3%) and retinal vasculitis (2 eyes, 13.3%). (2) Multimodal imaging features: SD-OCT in ASPPC consistently showed outer retinal disruption and ellipsoid zone loss, while FFA revealed characteristic early hypofluorescence with late speckled hyperfluorescence and leakage; optic perineuritis showed early disc hyperfluorescence with marked late-phase leakage; and retinal vasculitis demonstrated arterial wall staining with peripheral non-perfusion. (3) Visual outcomes: Following treatment, 14 eyes (93.3%) showed visual improvement, with median BCVA improving from 0.40 to 0.00 logMAR (P < 0.001). The initial misdiagnosis rate was 60% (6/10).

Conclusions: In patients presenting with ocular syphilis as the initial manifestation, ASPPC is the most common posterior segment lesion. Multimodal imaging provides critical diagnostic clues. Despite frequent initial misdiagnosis, prompt penicillin therapy yields favorable visual outcomes. Routine syphilis serology screening is strongly recommended for any patient with unexplained posterior uveitis or optic neuropathy.