Objectives: to investigate the clinical and biological features of giant congenital melanocytic nevus at National Hospital of Dermato-Venereology and Saint Paul Hospital from Jan, 2006 to Oct, 2010. Material and Method: a cross-sectional study based on data of 30 patients hospitalized at the two hospital. Result: Giant congenital melanocytic nevus are common in women accounting for 66.67 percent. The characteristic dinial features of that disease are: well define, dark color and rough surface with a lot of black hair.There are 13 percent of them had more than 100 setllite lesion
23 percent lesions located on the malignance area and 20 percent of cases had abnormal progressive. All of the case are dermal melanocytic vevus and all of them positive to 5100 and HMB-45.