Cutaneous malignant melanoma arising in an acquired naevus of Ota.

Naevus of Ota is a dermal melanocytosis most commonly found in black or Asian skin and is usually a benign malformation, but with a low risk of melanoma. We describe a 32-year-old Caucasian man with an acquired naevus of Ota with subtle pigmentation, in which a melanocytic papule developed. The lesion, deceptively, had no clinically suspicious features, but investigation revealed an aggressive cutaneous malignant melanoma, extensive orbital ring melanocytosis and metastatic brain and subsequent liver disease.

UV radiation-induced immunosuppression is greater in men and prevented by topical nicotinamide.

UV radiation-induced immunosuppression augments cutaneous carcinogenesis. The incidence of skin cancer continues to increase despite increased use of sunscreens, which are less effective at preventing immunosuppression than sunburn. Using the Mantoux reaction as a model of skin immunity, we investigated the effects of solar-simulated (ss) UV and its component UVA and UVB wavebands and tested the ability of topical nicotinamide to protect from UV-induced immunosuppression. Healthy, Mantoux-positive volunteers were UV-irradiated on their backs, with 5% nicotinamide or vehicle applied to different sites in a randomized, double-blinded manner. Subsequent Mantoux testing at irradiated and adjacent unirradiated sites enabled measurement of UV-induced immunosuppression with and without nicotinamide. Suberythemal ssUV caused significant immunosuppression, although component UVB and UVA doses delivered independently did not. Men were immunosuppressed by ssUV doses three times lower than those required to immunosuppress women. This may be an important cause of the higher skin cancer incidence and mortality observed in men. Topical nicotinamide prevented immunosuppression, with gene chip microarrays suggesting that the mechanisms of protection may include alterations in complement, energy metabolism and apoptosis pathways. Nicotinamide is a safe and inexpensive compound that could be added to sunscreens or after-sun lotions to improve protection from immunosuppression. immunosuppression.JID JOURNAL CLUB ARTICLE: For questions, answers, and open discussion about this article, please go to http://network.nature.com/group/jidclub