The presence of iris pigmented lesions in individuals <40 years of age increases the likelihood for development of cutaneous melanoma by approximately 1.8-fold, with that risk rising proportionately with the number of such lesions, according to results of a recent case-control study published in the British Journal of Dermatology.
A total of 1254 Australians of European background were assessed for sun exposure and melanoma. Of these,1117 had iris photographs of sufficient quality to be evaluated for the presence of pigmented lesions.
Most participants had fair skin, with a varying degree of sunburn propensity and tanning response. Mean patient age was 47 years; 51.5% of the participants were women.
Based on digital photographic images, the most common eye color was blue/gray (66.4%), followed by green/hazel (23.4%) and brown (10.1%). The majority (76%) of participants’ eyes examined had ≥1 pigmented lesion. Iris pigmented lesions were detected more often in green/hazel eyes, but this did not differ significantly according to skin color after adjusting for iris color.
Participants >40 years had numbers of iris pigmented lesions similar to age-matched controls (mean 5.7 lesions vs 5.2 lesions, respectively; P =.02). However, younger participants and controls (≤40 years of age) had a significantly greater difference in the number of iris pigmented lesions (mean 3.96 lesions vs 2.19 lesions, respectively; P =.004). Moreover, the presence of ≥3 iris pigmented lesions increased the risk for melanoma 1.45-fold (95% CI, 1.07-1.95; P =.02).
The investigators concluded that iris pigmented lesion count provides predictive information for melanoma risk stratification beyond currently used factors such as skin type, hair color, eye color, and nevus count.
The study findings suggest that a detailed dermatologic examination for melanoma may be reasonable in individuals <40 years of age with iris pigmented lesions. Additional studies are warranted to further define this association, which includes identification of those genes that influence the formation of iris pigmented lesions.
Laino AM, Berry EG, Jagirdar K, et al. Iris pigmented lesions as a marker of cutaneous melanoma risk: an Australian case-control study [published online January 8, 2018]. Br J Dermatol. doi: 10.1111/bjd.16323