Multimodal Imaging of Choroidal Lymphoma: Diagnostic Features, Differential Diagnosis, and Clinical Monitoring

Choroidal lymphoma is a rare intraocular malignancy that often presents with subtle and nonspecific clinical signs, frequently masquerading as inflammatory or metastatic choroidal disease and leading to delayed diagnosis. Because histopathologic confirmation is not always immediately feasible, multimodal imaging plays a pivotal role in raising clinical suspicion, guiding differential diagnosis, and monitoring disease activity. This narrative review summarizes current evidence regarding characteristic imaging findings of choroidal lymphoma across available modalities, including color fundus photography, ultra-widefield imaging, fundus autofluorescence, enhanced depth and swept-source optical coherence tomography, fluorescein angiography, indocyanine green angiography, OCT angiography, and ultrasonography. Multimodal imaging reveals a consistent pattern of primary choroidal infiltration associated with secondary retinal pigment epithelium and retinal alterations. Choroid-focused OCT typically demonstrates diffuse or placoid choroidal thickening with homogeneous hyporeflective infiltration and loss of normal vascular architecture, often accompanied by subretinal fluid and RPE irregularities. ICGA frequently shows multifocal hypofluorescent lesions extending beyond clinically visible disease, highlighting widespread choroidal involvement and commonly displaying OCT-ICGA incongruence. FAF documents secondary RPE dysfunction with patchy autofluorescence abnormalities, while ultrasonography corroborates structural thickening and may detect extrascleral extension. The integration of multimodal imaging allows earlier recognition of choroidal lymphoma, improves differentiation from key mimickers such as melanoma, metastasis, and inflammatory choroidopathies, and supports longitudinal monitoring of treatment response. Although tissue confirmation remains essential whenever feasible, multimodal imaging represents a cornerstone of contemporary diagnostic strategy.