Multimodal imaging of tumour-related lipid exudation and exudative retinal detachment following brachytherapy in choroidal melanoma

Choroidal melanoma is the most common primary intraocular malignancy, accounting for 90% of all uveal melanomas. Although radiation therapy (brachytherapy, proton beam and gamma knife) is a standard and effective treatment for choroidal melanomas, it carries a risk of vision-threatening complications such as cataract, optic neuropathy, and radiation retinopathy. A lesser-known complication is tumor-related lipid exudation (TRLE), characterized by subretinal and intraretinal lipid accumulation following radiotherapy, potentially resulting from radiation-induced vasculopathy and increased vascular permeability. We report a case of a 61-year-old man with a long-standing choroidal nevus under observation for 15 years. Due to signs of growth and subretinal fluid detected on OCT, malignancy was suspected, and Ruthenium-106 brachytherapy was performed. One-month post-treatment, the patient developed progressive exudative retinal detachment with lipid exudation, despite preserved visual acuity. At the nine-month follow-up, worsening exudation and tumor growth were observed, prompting a second brachytherapy session and intravitreal aflibercept injections every eight weeks, leading to complete resolution of lipid exudation and restoration of retinal anatomy. Six months post-treatment, the tumor remained flat, and visual acuity improved to 20/20. TRLE is an underrecognized complication of radiation therapy for choroidal melanoma, with risk factors including pre-radiotherapy subretinal fluid, increased tumour thickness, and Bruch's membrane rupture. Studies suggest that anti-VEGF therapy may help mitigate exudative complications; however, its efficacy remains uncertain. This case highlights the importance of recognizing TRLE as a potential complication of brachytherapy and underscores the critical role of multimodal imaging in early diagnosis and monitoring, ensuring optimal treatment outcomes for patients with choroidal melanoma.