Giant congenital melanocytic nevus: quantification of nevus debulking after split-thickness excision

Although giant congenital melanocytic nevi (CMN) may undergo malignant transformation, their complete surgical removal is commonly difficult to achieve and may require sacrifice of normal skin. We treated a patient with CMN by a combination of full-thickness excision and primary closure of the central atypical portion and split-thickness excision of the remainder. Histometric analysis of the tissues obtained at surgery indicated that the split-thickness procedure removed approximately 70% of the cellular nevus content from that area. Total debulking by the combined procedure was calculated to be approximately 80%. If the risk of malignant degeneration is proportional to the number of melanocytes present, the debulking procedure described may provide a useful alternative for the management of some giant CMN. The cosmetic result is satisfactory and the significant lightening in color and removal of nodular irregularities may facilitate prospective follow-up of the residual lesion.