A 53-year-old man was diagnosed with a symptomatic circumscribed choroidal hemangioma and secondary retinal detachment on the basis of typical findings on fundus examination (Figure 1), indocyanine green angiography, and ultrasonography.1 External proton beam irradiation at a dose of 20 Gy (to convert to rad, multiply by 100) in 4 sessions was planned, preceded by tantalum clip surgery.2 Peroperative transillumination showed the tumor to be transparent. On the first day after the uneventful tantalum clip surgery, the tumor color had changed from red-orange to dark gray, reminiscent of choroidal melanoma (Figure 2). Controlled fundus examination 2 weeks later revealed a red-orange color again (Figure 3), supporting the diagnosis. Proton beam irradiation was performed as planned.