Acute posterior multifocal placoid pigment epitheliopathy following influenza vaccination

Dear Editor, Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE) is an uncommon inflammatory choriocapillaropathy affecting predominantly young adults and presenting with acute visual disturbances. First described by Gass in 1968, APMPPE is characterized by creamy-white placoid lesions at the level of the retinal pigment epithelium (RPE) and choriocapillaris.[1] The estimated incidence is 0.15 cases per 100,000 individuals, typically affecting otherwise healthy patients in the second to fourth decades of life.[2] Although the etiology remains uncertain, an immune-mediated mechanism has been suggested, and postvaccination cases have been reported. We describe a case of bilateral, macula-threatening APMPPE occurring 2 days after influenza vaccination, with excellent structural and visual recovery after corticosteroid therapy. A 37-year-old woman presented with bilateral blurred vision, metamorphopsia, and floaters for 5 days. She had received an influenza vaccine (Sanofi S.A.) 2 days before symptom onset. Her medical history was unremarkable. Best-corrected visual acuity (BCVA) was 6/6 in both eyes. Anterior segment examination was normal. Funduscopy revealed multiple cream-colored placoid lesions in the posterior poles of both eyes, more prominent near the fovea in the left eye [Figure 1].Figure 1: Initial examination findings. Color fundus photography demonstrating discrete placoid lesions located at the posterior pole of both the Right eye (a) and the left eye (b), with lesions more macula-threatening in the left eye (b). Optical coherence tomography images demonstrating multifocal outer retinal and IS-OS line disruption with subretinal hyperreflective material depositions in both the right eye (c) and the left eye (d). IS/OS: Inner segment/outer segmentOptical coherence tomography (OCT) showed focal outer retinal disruption, loss of the ellipsoid zone, and subretinal hyperreflective materials [Figure 1]. Fluorescein angiography demonstrated early hypofluorescence with late hyperfluorescent staining, and indocyanine green angiography revealed more diffuse hypocyanescence. Fundus autofluorescence (FAF) showed hyperautofluorescent borders with central hypoautofluorescence. OCT angiography revealed patchy choriocapillaris flow deficits [Figure 2].Figure 2: Fundus fluorescein angiography and indocyanine green angiography (ICGA): Early-phase images of the right (a) and left (b) eyes, respectively, demonstrating typical hypofluorescence corresponding to placoid lesions; Late-phase images of the right (c) and left (d) eyes demonstrate irregular and discrete hyperfluorescent margins with lesion leakage on FA, while corresponding lesions appeared hypofluorescent on ICGA. Fundus Autofluorescent (FAF) of both right (e) and left (f) eyes shows classic placoid lesion of hypoautofluorescent center with retinal pigment epithelium (RPE) damage or blockage and hyperautofluorescent border with active inflammation or RPE stress. Optical Coherence Tomography Angiography demonstrated choriocapillaris perfusion deficits in both the right eye (g) and the left eye (h), with more pronounced ischemia observed in the right eyeLaboratory workup was entirely normal, including complete blood count, kidney and liver function testing, tuberculosis screening, Serologic Test of Syphilis-Rapid Plasma Reagin/ Treponema Pallidum Particle Agglutination (STS-RPR/TPPA), viral serology (herpes simplex virus, varicella zoster virus, cytomegalovirus, human immunodeficiency virus), toxoplasma serology, and autoimmune markers (Antinuclear antibody [ANA], complement levels, rheumatoid factor, beta-2 microglobulin, and human leukocyte antigens [HLA]-B27). Chest radiography showed no abnormalities. No evidence of systemic infection, vasculitis, or autoimmune disease was identified. A diagnosis of APMPPE was made based on typical multimodal imaging findings. Oral prednisolone was initiated at 0.4 mg/kg/day and tapered over 2 weeks. The patient experienced rapid improvement in visual distortion and scotoma. At 8 weeks, BCVA remained 6/6 bilaterally with substantial restoration of the outer retina and resolution of placoid lesions [Figure 3]. At 5 months, there was no recurrence or structural sequelae.Figure 3: Five months posttreatment: Fundus examination of the right (a) and left (b) eyes; Optical coherence tomography scans of the right (c) and left (d) eyes and Fundus Autofluorescence (FAF) of the right (e) and left (f) eyes. All modalities showed significant regression of the lesions, with residual changes observedAlthough APMPPE often resolves spontaneously, macular involvement can lead to lasting photoreceptor or RPE damage. Corticosteroids are therefore commonly used when lesions threaten the fovea.[3] Multimodal imaging studies support the hypothesis that choriocapillaris ischemia leads to secondary RPE and photoreceptor dysfunction, which corresponds to the outer retinal abnormalities observed on OCT.[4] Reports of postvaccination APMPPE are rare, and a summary of previously documented cases is provided in Table 1. The temporal proximity of symptom onset to influenza vaccination suggests a possible immune-mediated trigger. Although causality cannot be established, proposed mechanisms include delayed-type hypersensitivity and immune activation targeting the choriocapillaris. Our patient’s course is consistent with previously reported postvaccination cases, which often demonstrate bilateral involvement, choriocapillaris flow deficits, and disruption of outer retinal layers. A key value of this report is the demonstration of rapid clinical and structural recovery following prompt corticosteroid therapy, with the patient achieving a full recovery of both visual acuity and outer retinal architecture at the 5-month follow-up. While some cases in the literature report residual RPE changes or secondary complications, our case highlights that early intervention when the macula is threatened can lead to excellent long-term outcomes.Table 1: Literature review of reported cases of postvaccination acute posterior multifocal placoid pigment epitheliopathyAPMPPE appears to be less frequently encountered in Taiwan compared to Western countries. In East Asian populations, inflammatory conditions such as HLA-B27-associated anterior uveitis and Vogt–Koyanagi–Harada disease show a much higher prevalence. The rarity of APMPPE in our region underscores the importance of this report; clinicians must maintain a high index of suspicion for placoid syndromes to avoid misdiagnosis and overtreatment. In conclusion, this case illustrates a typical bilateral APMPPE presenting 2 days after influenza vaccination, with complete recovery following prompt corticosteroid therapy. Clinicians should consider APMPPE in patients presenting with acute visual symptoms shortly after vaccination and initiate urgent multimodal imaging and treatment when macular involvement is evident. Ethical statement The study was reviewed and granted an exemption from full IRB review by Shin Kong Wu Ho-Su Memorial Hospital due to its retrospective design and anonymized data analysis (Approval No. T-20250704). Declaration of patient consent This study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki and its amendments. The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published, and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Data availability statement The datasets generated during and/or analyzed during the current study are not publicly available, but are available from the corresponding author on reasonable request. Financial support and sponsorship Nil. Conflicts of interest The authors declare that there are no conflicts of interests of this paper.