A 54-year-old woman developed an orbital mass 20 years after enucleation of the left eye for a choroidal melanoma, which proved to be of spindle-A type. Computed tomography of the orbit suggested the diagnosis of a cavernous hemangioma, but orbital biopsy confirmed the diagnosis of recurrent malignant melanoma and the patient was managed by orbital exenteration followed by radiotherapy. The orbital recurrence was of the mixed cell type, suggesting a gradual 20-year transition of the spindle-A cells to spindle-B and epithelioid cells. We recommend that the selected surgical management of extrascleral extension of uveal melanomas be determined by the degree of extrascleral involvement and by whether the extrascleral extension is discovered clinically, at surgery, or in the pathology laboratory. We recommend that orbital computed tomography be performed periodically after enucleation in all patients who have orbital extension of uveal melanomas.