Seasonal pattern of the excision rate of melanoma and naevi

Based on available information that melanocytic skin lesions presenting a j unctional component are more susceptible to the influence of ultraviolet ra diation, this study compares the seasonal differences between the excision rates of melanocytic skin lesions with a junctional component to those with out. The histological diagnoses of 1230 patients with melanocytic skin lesi ons were retrospectively analysed. Depending on the histological diagnosis four groups were formed: melanomas, dysplastic naevi, common naevi (junctio nal and compound naevi), and dermal naevi. All dates of operations were all ocated to summer or winter halves of the year. The collected data were comp uter analysed for statistical description. The number of excisions of melan ocytic lesions with a junctional component (melanoma, dysplastic naevi, com mon naevi) showed an impressive seasonal variation, with a peak during the summer months, while the excision frequency of dermal naevi was approximate ly constant during the year. In conclusion, we suggest that ultraviolet rad iation may contribute to the seasonal pattern of excision of melanoma and n aevi only when a junctional component is present. (C) 2001 Lippincott Willi ams & Wilkins.