A Case of Retinal Detachment with Unique Optical Coherence Tomography Findings after Gamma Knife® Radiosurgery Treatment for Choroidal Melanoma

Purpose: To report a case of retinal detachment with unique optical coherence tomography (OCT) findings after Gamma Knife® (GK; Elekta Instrument AB, Stockholm, Sweden) treatment for choroidal melanoma (CM). Case Report: A 48-year-old woman underwent GK therapy for CM in her right eye from the macula to the temporal side. While the tumor subsequently shrank, the patient developed radiation retinopathy, which was treated with laser photocoagulation. The tumor lesions later subsided; however, her visual acuity (VA) decreased 8 years after the initial treatment. Although the tumor lesions in the right eye had become scarred, a bullous retinal detachment with fixed folds occurred in the superior-nasal quadrants. OCT examination revealed a preretinal membrane, vitreoretinal traction, and an inner retinal break; however, no outer retinal break was clearly detectable. MRI scans showed no increase in tumorous lesions, and 123I-IMP SPECT imaging showed no photon accumulation. Thus, it was determined that there was no tumor activity. The corrected VA in her right eye was light perception, and it was determined that there was no indication for vitreous surgery. Conclusion: In this case, an inner retinal break was formed by the vitreoretinal traction around the scarred tumor and radiation retinopathy, thus suggesting the possibility of the development of a rhegmatogenous retinal detachment presumably complicated with an outer retinal break.