GLUT-1-negative Choroidal Malignant Melanoma with Liver Metastasis Recurrence 12 Years after Surgery without FDG Accumulation in a Recurrent Lesion on FDG-PET/CT.

Choroidal malignant melanoma is a rare malignant tumor that develops in adult eyeballs. It causes early lymph node and distant metastasis. Fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (CT) is widely used for screening malignant melanoma metastases. We encountered a 58-year-old man with choroidal malignant melanoma in whom liver metastasis recurred 12 years after surgery, without any observable FDG accumulation. Immunostaining revealed the absence of glucose transporter type 1 (GLUT-1) expression, crucial for intracellular FDG uptake. The lack of FDG accumulation in the lesion could be attributed to the diminished cellular FDG uptake due to the absence of GLUT-1 expression.