A Case of Choroidal Melanoma Resulted in Eyeball Enucleation 2 Years after Carbon Ion Radiotherapy Due to Local Recurrence.

Background: Recently, carbon ion radiotherapy (CIR) has become the standard therapy for choroidal melanoma to preserve the eyeballs in Japan. We report a case of choroidal melanoma resulting in eyeball enucleation 2 years after carbon ion radiotherapy due to local recurrence. Case: A 64-year-old man was referred to Tokyo Medical University hospital with a diagnosis of choroidal tumor. Intraocular tumor was located at the equator of temporal area in ocular fundus. After systemic work-up, clinical diagnosis of choroidal melanoma was made and CIR was applied. After CIR, the intraocular tumor was stable for 2 years. However, 2 years and 3 months after CIR, local recurrence of the tumor was detected. Eventually, the eyeball was enucleated. Histopathologically, the original lesion was composed of melanoma cells containing abundant melanin pigments, and these cells were positive for HMB-45, Melan-A and S-100 protein. In contrast, the recurrent lesion showed lack of melanin pigment and proved less positive for HMB-45, Melan-A and S-100 protein. Four months after enucleation, the patient developed liver metastasis and received the appropriate supportive care. Conclusions: Even after CIR with remission, choroidal melanoma can recur. Recurrent lesions of the tumor may reveal alternative histopathological findings compared to the original lesion.