Treatment of solar lentigo with cryosurgery.

Sir, Melanocytes are the skin cells most vulnerable to cold; they can be destroyed by temperatures of ± 4 to ± 73C (1). Lower tissue temperatures or repeated freeze ± thaw applications lead to skin necrosis (2). Selective destruction of melanocytic lesions by skin freezing can therefore be achieved without epithelial loss or skin necrosis if certain technical requirements are taken into account. In a randomized study of 20 patients, small benign pigmented lesions (lentigines) were shown to respond ef®ciently to a regimen of 5 s vs. 10 s contact cryosurgery at ± 423C skin surface temperature with good to excellent cosmetic results (3). Moreover, Stern et al. have documented signi®cant superiority of cryotherapy over CO2 and argon laser treatments in a randomized study with 99 lentigines in 13 patients (4). We report here on the successful treatment of 6 patients with large solar lentigo lesions using nitrous oxide contact cryosurgery. To our knowledge, the application of cryosurgery has not previously been evaluated for this indication.