Usual presentation of unusual masquerade – A choroidal lymphoma

A 61-year-old Caucasian male was referred for marked asymmetry in retinal appearance with increasing soft drusen-like lesions in the right eye. There was no blurring of vision or floaters. His vision was -0.1 LogMAR in both eyes with quiet anterior and posterior chambers. Fundus examination in the right eye showed multifocal, mid-peripheral, yellowish, creamy circular chorioretinal lesions [Fig. 1a], with corresponding hyper autofluorescence [Fig. 1b]. The left eye was normal. Optical coherence tomography (OCT) macula was normal in both eyes [Fig. 1c], and he was observed without intervention.Figure 1: (a) Shows right eye fundus with multifocal, mid-peripheral, yellowish, creamy circular chorioretinal lesions. (b) Shows corresponding areas of hyperautofluorescence. (c) Shows normal OCT macula scanOne year later, he reported blurred vision in the right eye. Fundus examination appeared stable, but OCT showed choroidal thickening [Fig. 2a] with a normal B-scan [Fig. 2b], raising suspicion for choroidal lymphoma. After being lost to follow-up, he returned with further vision loss. Fundus revealed hypopigmented choroidal spots and macular folds. OCT demonstrated thickening of the choroid with undulating “seasick” folds, suggesting choroidal lymphoma [Fig. 2c].Figure 2: (a) Shows thickening of choroid on OCT macula scan. (b) Shows normal choroidal thickness on B scan ultrasonography. (c) Shows OCT macula scan with thickening of the choroid with undulating “seasick” folds, suggestive of choroidal lymphomaWhat to do next? MRI with contrast Choroidal biopsy PET scan HLA A29. He was referred for an MRI of the orbit [Fig. 3a] and brain with contrast, which ruled out orbital and CNS lymphomas. Transretinal choroidal biopsy confirmed low-grade B-cell lymphoma. PET scan excluded systemic (extraocular) disease, confirming primary ocular lymphoma. He was referred for External Beam Radiotherapy (EBRT), which showed a good response [Fig. 3b].Figure 3: (a) Shows MRI orbit, ruling out other orbital or extraocular lymphoma. (b) Shows OCT macula scan post EBRT, showing reduced choroidal thickeningDiagnosis: Primary Choroidal Lymphoma. Answer: A. Case Discussion Early diagnosis of choroidal lymphoma (CL) is challenging due to subtle presentation and frequent misdiagnosis as uveitis or central serous chorioretinopathy.[1] A key indicator is multifocal creamy-yellow choroidal patches. Autofluorescence typically reveals granular hyperautofluorescent spots with surrounding hypoautofluorescence. Ultrasonography is a valuable non-invasive tool, often showing acoustically hollow choroidal thickening. Enhanced depth OCT detects infiltration with variable topography: Flat when thin (1.7 mm), rippled when thicker (2.8 mm), and “seasick” at maximum thickness (4.1 mm).[2] Definitive diagnosis requires biopsy with histopathology, ideally processed within 30 minutes for cell viability. The sample should be as large as possible and ideally taken from the deeper part of the lesion, near the choriocapillaris, where viable lymphoma cells are most likely to be found. Immunohistochemistry shows predominance of B-lymphocytes (usually atypical in morphology) on a background of macrophages and lysis, in contrast to reactive inflammation in the vitreous, which shows dominant T-cells.[3] Systemic evaluation, including MRI, is essential to rule out CNS involvement. Treatment is not standardised due to its rarity. Systemic chemotherapy and immunotherapy (e.g., rituximab) are reserved for systemic disease, while localised choroidal lymphoma is best managed with EBRT. The prognosis for primary CL is generally favourable, with a 2-year survival outlook. Conclusion High suspicion based on OCT and fundus findings is essential for early recognition. Prompt systemic evaluation ensures timely management and exclusion of systemic lymphoma. Authors' contributions Prajakta Thakur: Contributed to the concept and design of the manuscript, collected and organised the clinical data, conducted an extensive literature search, and prepared a detailed case description. She was actively involved in manuscript preparation, figure preparation, and editing, and provided substantial intellectual input throughout the drafting process. Paritosh Shah: Contributed to the concept and design of the manuscript, conducted patient evaluation and clinical examination, and was involved in data interpretation and clinical diagnosis. He provided critical intellectual content, contributed to manuscript drafting, and reviewed and approved the final version of the manuscript. Declaration of patient consent The authors certify that they have obtained all appropriate consent from the patient for his/her images and other clinical information to be reported in the journal. The patient understands that his/her name and initials will not be published, and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.