Cutaneous Halo Nevi Following Plaque Radiotherapy for Uveal Melanoma

Halo nevi have been described in both dermatology and ophthalmology.^1,2 Cutaneous halo nevi are found more often in children than adults and are believed to result from an immune response.³ Choroidal halo nevus represents 5% of all choroidal nevi and displays low risk for transformation to melanoma.⁴ The development of cutaneous halo nevi or vitiligo in adulthood can occur following treatment of cutaneous melanoma and correlates with decreased morbidity, presumably due to activation of a systemic immune response.⁵ There have been rare reports of vitiligo and/or cutaneous halo nevi development following enucleation for uveal melanoma.^6,7 A comprehensive study on choroidal halo nevi found a statistical association with history of skin melanoma.² Herein, we describe a young woman with uveal melanoma who developed a halo ring around numerous pigmented cutaneous nevi following plaque radiotherapy for uveal melanoma.

A 28-year-old woman with photopsia in the left eye was diagnosed as having choroidal melanoma. There was no history of cutaneous melanoma. Visual acuity was 20/20 OD and 20/25 OS. The melanoma measured 14 mm in basal dimension and 7 mm in thickness (Figure, A).

Iodine 125 plaque radiotherapy was performed. Two months after therapy, the patient reported development of a noninflammatory, painless, circumscribed halo around numerous previously pigmented cutaneous nevi, and 1 nevus lost nearly all pigmentation (Figure, B-E). At 4 months, the uveal melanoma regressed to 3.7 mm in thickness. Metastatic evaluation findings were negative.

Cutaneous melanoma can stimulate vitiligo or halo nevi through immune mechanisms. The proposed pathophysiology involves cytotoxic T-cell–mediated immune reaction targeted against antigens shared between normal melanocytes and melanoma cells such as MART-1, tyrosinase, gp100, TYRP1, and TYRP2.¹ Histopathologically, a lymphohistiocytic infiltrate predominated by CD4 and CD8 T cells has been observed at the margin of such depigmented lesions.¹ Immunotherapeutic strategies for cutaneous melanoma have been attempted based on this observation.¹

In 1968, Nirankari et al⁸ described a 57-year-old man who underwent evisceration for panophthalmitis from undetected uveal melanoma. He developed vitiligo at 9 years and orbital recurrence of uveal melanoma at 11 years, for which orbital exenteration was performed. In 1982, Albert et al⁶ described 2 patients with skin depigmentation following enucleation for melanoma. Case 1 was a 69-year-old man who developed vitiligo 5 years after enucleation, and case 2 was a 36-year-old man who developed cutaneous halo nevi 1 year after enucleation. Albert and colleagues speculated that this represented a heightened host response and more favorable prognosis. In 2004, Duh et al⁷ described a 74-year-old woman with a 12.8-mm-thick uveal melanoma who developed vitiligo 6 years after enucleation. These reports suggest a possible role of the immune system following therapy of uveal melanoma, similar to cutaneous melanoma. We are not aware of other cases of cutaneous halo nevi developing after plaque radiotherapy for uveal melanoma.

The association of cutaneous halo nevus or vitiligo with treated uveal melanoma could be more frequent because these dermal findings can be subtle, as in our case.

Correspondence: Dr C. L. Shields, Department of Ocular Oncology, Wills Eye Institute, Thomas Jefferson University, 840 Walnut St, Ste 1440, Philadelphia, PA 19107 (carol.shields@shieldsoncology.com).

Funding/Support: This study was supported by the Eye Tumor Research Foundation, Philadelphia, Pennsylvania.