Abstract
Purpose :
Differences in tumor location and prognosis have been described for uveal melanoma in blue versus brown eyes. [1, 2] Green eyes are often not mentioned. However, when analysing the type of melanin, green and blue eyes show similar levels in quantity and ratio of eumelanin and pheomelanin, with brown eyes showing higher levels.[3] We wondered whether uveal melanoma in green eyes were more similar to UM in blue eyes than in brown eyes.
Methods :
We performed a retrospective cohort study and analyzed 237 eyes that have been primarily enucleated for UM. Of this cohort, 157 had blue/grey, 41 green/hazel and 39 (dark)brown irises. We compared clinical and histological data. Pigmentation was derived from the histological report.
Results :
UM in green eyes (n = 41) tended to be less frequently located in the ciliary body (P = 0.05), but otherwise were clinically not significantly different from blue/grey (n =157) or brown eyes (n =39). Also, survival of UM patients with green eyes was not significantly different compared to UM in blue- or brown eyed patients (P = 0.935). However, a clear difference was observed with regard to pigmentation. Histopathologically, 72% Of the UM eyes with green irises had minor to no pigmentation, compared to 26% and 53% in UM eyes with a (dark)brown iris and blue/grey iris, respectively (P <0.001).
Conclusions :
The degree of pigmentation of a uveal melanoma is related to the color of the iris. UM-containing eyes with a brown or dark brown iris reveal high levels of pigmentation, with UM in eyes with green irisis showing much less pigment. This finding is also of clinical relevance to the treatment of UM, since treatment with photodynamic light therapy (PDT) is significantly influenced by the degree of pigmentation in the tumor.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.