Acute Outer Retinopathy Revealing Metastatic Small-Cell Lung Carcinoma: An Atypical Paraneoplastic Retinopathy within the Inflammatory Spectrum

PURPOSE: To describe the longitudinal multimodal imaging findings of a case of acute outer retinopathy (AOR), a distinctive phenotype of outer retinal alteration, which revealed an underlying metastatic small-cell neuroendocrine lung carcinoma. METHODS: Case report. RESULTS: A 60-year-old woman presented with rapidly progressive bilateral vision loss, photopsia, and peripheral visual field constriction. Best-corrected visual acuity was 20/50 in the right eye (OD) and counting fingers in the left eye (OS) at baseline, improving to 20/25 OD and 20/32 OS at final follow-up. Ophthalmoscopic examination revealed sharply demarcated, sectoral, and perivenular yellow-grayish outer retinal lesions. Fundus autofluorescence demonstrated hyperautofluorescent perivenular lesions, while optical coherence tomography demonstrated the angular sign of Henle fiber layer hyperreflectivity (ASHH), outer nuclear layer thinning, and ellipsoid zone (EZ)/ interdigitation zone (IZ) disruption with preservation of the retinal pigment epithelium. Fluorescein angiography revealed delayed venous filling without leakage, and indocyanine green angiography was unremarkable. The patient was diagnosed with AOR. Systemic corticosteroid therapy resulted in relative stabilization of lesion extent and partial recovery of the central EZ/IZ. Subsequent systemic evaluation disclosed metastatic small-cell neuroendocrine lung carcinoma. CONCLUSION: Perivenular AOR may be difficult to recognize clinically, and correlation of multimodal imaging findings is essential for accurate diagnosis. This case highlights the potential paraneoplastic association of AOR with systemic malignancy and underscores the importance of appropriate systemic investigation, guided by clinical context, to identify an underlying neoplasm.