- Case Overview: A 15-year-old boy presented with acute posterior multifocal placoid pigment epitheliopathy (APMPPE), a rare inflammatory chorioretinal disorder, experiencing severe bilateral vision loss.

- Initial Symptoms: After 2 weeks of sinus congestion, the patient had rapid vision deterioration over 2 days, initially with 20/20 vision bilaterally, which worsened to 20/500 (right eye) and 20/600 (left eye) within a week.

- Clinical Findings: Examination revealed creamy-white placoid lesions in both posterior poles, mild vitritis in the right eye, hypoautofluorescence lesions with hyperautofluorescence rims on fundus autofluorescence, and early blockage with late staining on fluorescein angiography.

- Diagnosis Confirmation: Optical coherence tomography (OCT) showed outer retinal disruptions and thinning, consistent with APMPPE.

- Treatment: Due to severe vision loss, the patient was started on oral prednisone, later transitioned to mycophenolate mofetil within 2 months to minimize steroid side effects.

- Disease Progression: Vision remained poor (20/200 right, 20/300 left) beyond a 5-month follow-up despite lesion fading and outer retinal reconstitution on OCT.

- Recovery: By 8 months, visual acuity improved to 20/20 bilaterally with no recurrences, suggesting a protracted but successful recovery.

- Typical APMPPE Characteristics: Usually affects individuals in their 20s-40s, presents with acute bilateral vision loss, and resolves within months without treatment, though some experience residual symptoms like metamorphopsia or scotomas.

- Atypical Aspects of This Case: Young age (15), severe and prolonged vision loss, and extended recovery time compared to the typical APMPPE course.

- Differential Diagnoses: Included macular serpiginous choroidopathy (recurrent, poor prognosis) and relentless placoid chorioretinitis (prolonged activity), but lesion distribution and onset aligned with APMPPE.

- Treatment Rationale: Aggressive immunosuppression was chosen due to the threat of permanent vision loss in a young patient; mycophenolate mofetil was used as a novel steroid-sparing option.

- Outcomes and Implications: The case suggests that steroids and immunosuppression may benefit severe APMPPE cases, challenging the idea that healing plateaus after 4 weeks, though no definitive guidelines exist.

- Literature Context: Half of reported APMPPE cases receive corticosteroids, but efficacy remains unclear; this is the first reported use of mycophenolate mofetil for APMPPE.

- Conclusion: This unusual case highlights the potential for delayed but full visual recovery in APMPPE with immunosuppression, calling for further research into treatment protocols for severe cases.