The prevalence and characteristics of congenital pigmented lesions in newborn babies in Oxford

Abstract

Melanocytic naevi (MN) are recognised risk factors for malignant melanoma but the epidemiology of MN is poorly understood. Some MN are present at birth and the study of congenital lesions is an important first step toward understanding the development of MN in early life. In this study, the prevalence and characteristics of congenital pigmented lesions were documented in 1012 White caucasian newborn babies at a maternity hospital in Oxford. Only 12 babies (1.2%) were found to have pigmented skin marks and each of these had only one lesion and no other abnormalities. MN were identified with certainty in only five babies (0.5% of the population; 95% CI, 0.06%-0.93%) thus confirming the relatively low prevalence of this lesion. Four of the MN were noted to be 'small' (less than 15 mm diameter) and all five were less than or equal to 20 mm in diameter. In other respects, the MN displayed a diversity of features. Of the other lesions there were two Mongolian blue spots, one melanocytic pustule, one 'probable' MN and three unusual skin marks where the diagnosis was uncertain but considered unlikely to be MN. During the course of the study, examinations were also carried out incidentally on 39 non-White babies. Twenty-two of these were noted to have Mongolian spots (57%) and three had other pigmented lesions (8%).