A case of acute syphilitic posterior placoid chorioretinitis showing improved choroidal blood flow after treatment

PURPOSE: Acute syphilitic posterior placoid chorioretinitis (ASPPC) is a rare form of ocular syphilis. However, its pathophysiology is not fully understood. Laser speckle flowgraphy (LSFG) can facilitate the non-invasive evaluation of blood flow and allow investigations into the effects of treatments in various ocular diseases. We report a case of ASPPC that presented with symptoms only in the right eye but showed bilateral disease in LSFG. OBSERVATIONS: A 54-year-old man presented with decreased vision and visual field defects in the right eye 2 days prior to the initial visit. Fundoscopy images showed a typical yellowish placoid lesion in the macular area, and optical coherence tomography showed disruption of the outer retinal layers and nodular appearance of the retinal pigment epithelium. Fluorescence angiography showed excessive leakage of the placoid lesion characterized by hypofluorescent dots in the inner area (“leopard spotting”). The patient was diagnosed with unilateral ASPPC based on multiple imaging and serological tests. Penicillin was administered for 2 weeks, and the patient showed improvement in symptoms and restoration of the retinal structure. The mean blur rate of the right/left eye was 2.1/5.9 arbitrary units (AU) before treatment and increased to 4.5/9.3 AU 6 months after treatment. CONCLUSIONS AND IMPORTANCE: Despite the absence of typical imaging signs and symptoms in the left eye, both eyes may have been affected with different degrees of severity. Thus, LSFG may facilitate the evaluation of treatment effects and the prediction of ocular inflammatory diseases in the early stages.