Intraocular Dissemination of Uveal Melanoma Cells Following Radiotherapy: Evolving Management Over the Past Decade

Post-Brachytherapy Pigment Dispersion in Uveal Melanoma

We report delayed intravitreal pigment dispersion following Iodine-125 plaque brachytherapy, without evidence of tumor recurrence, in 4 patients treated for choroidal melanoma. These patients were treated with Iodine-125 plaque brachytherapy, with or without transpupillary thermotherapy, and were followed clinically and using ancillary investigations for signs of tumor recurrence. All 4 patients were noted to develop pigment dispersion - it was detected on the surface of the retina (2 patients), diffusely in the vitreous (1 patient), or both (1 patient). Follow-up ranged from 70 to 343 months (mean 165 months; median 124 months) post-treatment with plaque brachytherapy, throughout which the location and amount of pigment remained grossly unchanged. None of the patients developed tumor recurrence or metastasis. We conclude that post-brachytherapy pigment dispersion is an unusual but known complication in the treatment of uveal melanoma. Close surveillance to rule out tumor recurrence and metastasis may be a reasonable line of management.

VITREOUS SEEDING OF CHOROIDAL MELANOMA

PURPOSE

To report a case of vitreous seeding in a medium-sized choroidal melanoma and review the literature.

METHODS

Observational case report and review of literature for pathogenesis, role of vitreous biopsy, and treatment outcomes.

RESULTS

A case of 57-year-old man diagnosed with vitreous seeding in the left eye 1 year after episcleral brachytherapy for medium-sized choroidal melanoma. The patient was initially diagnosed to have subretinal and vitreous hemorrhage due to rupture of a retinal artery macroaneurysm for which focal laser and intravitreal antivascular endothelial growth factor injections were administered. Over the next 9 months, the vitreous hemorrhage cleared and choroidal melanoma with retinal invasion became evident. One year after brachytherapy, the primary tumor regressed with resolution of surrounding subretinal fluid and hemorrhage. However, gradual decline in the visual acuity from 20/50 to 20/500 with increase of pigmented debris over the retinal surface and in the vitreous cavity was noted. A vitreous biopsy confirmed the presence of viable melanoma cells (epithelioid type), and the eye was enucleated. Histopathology showed microscopic persistence of primary tumor with diffuse vitreous seeding.

CONCLUSION

Vitreous seeding of choroidal melanoma poses a diagnostic and management challenge.