Abstract
Abstract: :
Purpose: Uveal melanoma is the most common primary eye cancer, and the most common site of melanoma besides the skin. While DNA damage caused by UV irradiation has been convincingly linked to cutaneous melanoma, it remains unclear whether UV irradiation is also an important risk factor for uveal melanoma. Cutaneous pigmentation is known to be protective against skin melanoma. This study was performed to investigate the analogous association between uveal pigmentation and posterior uveal melanoma. Methods: Prospective, cross-sectional study of 65 consecutive patients diagnosed with posterior uveal melanoma (melanoma group) and 218 consecutive patients diagnosed with retinal disease (control group), all of whom were Caucasian. A clinical grading system for estimating choroidal pigmentation was developed and histologically validated. Iris color and choroidal pigmentation were recorded for each patient. Results: In a clinical-histologic correlative study of 7 cases in which eyes were available after enucleation, darker choroidal pigmentation was strongly associated with increased size and density of melanocytic pigment granules, and increased density of choroidal melanocytes (correlation coefficient, r = 0.938). Patients in the melanoma group were more likely to have light iris color, but this trend was not statistically significant (p=0.084). Patients in the melanoma group were significantly more likely to have darker choroidal pigmentation than controls (p=0.045), and this association was more significant in the subgroup of patients with light iris color (p=0.005). Conclusion: Increased choroidal pigmentation, as a result of an increase in the density of pigmented choroidal melanocytes, is not protective but may actually be a risk factor for the development of posterior uveal melanoma in Caucasians. This finding may have important implications for understanding the role of UV irradiation in uveal melanomagenesis.
Keywords: 464 melanoma • 610 tumors • 345 choroid