Presumed Primary CD79B+ Vitreoretinal Lymphoma Mimicking an Ischemia-Like Macular Lesion

Purpose: To report a case of presumed primary vitreoretinal lymphoma (PVRL) mimicking an ischemia-like macular lesion. Methods: Single-patient case report. Results: A 74-year-old male patient presented with sudden vision loss up to the hand-motion level in his right eye. Fundus examination revealed a creamy, white-colored, ischemic-appearing macular area excluding the foveal region. Numerous vitreous cells and snowball-like opacities were observed. No relative afferent pupillary defect was evident, and no intraorbital mass or signs of active inflammation were revealed by contrast-enhanced cranial magnetic resonance imaging. Fluorescence angiography revealed a late-phase leopard-spot pattern of hyperfluorescence, whereas optical coherence tomography showed banded subretinal exudates with hyperreflective, vitelliform lesions within the retinal pigment epithelium. Cytological examination of the vitreous was negative for malignant cells. Using next-generation sequencing, the multigene mutation analysis revealed pathogenic CD79B , BTG2 , and PIM1 mutations, supporting the diagnosis of PVRL. Twenty-two months later, in response to visual acuity (best-corrected) reduction from 0.5 LogMAR (20/63) at baseline to hand motions, intravitreal methotrexate therapy was initiated in the left eye, which decreased the vitreous cell density. The right eye has since remained stable at 0.2 LogMAR (20/32). Conclusion: Presumed PVRL can mimic ischemic-appearing macular lesions and should be considered in the differential diagnosis of atypical ischemic retinal lesions. A thorough diagnostic workup should include multimodal imaging and cranial magnetic resonance imaging. When cytology is inconclusive, molecular genetic testing via NGS becomes a crucial tool, particularly when clinical suspicion remains high.