Neonatal malignant melanoma arising in a giant congenital nevus.

Introduction. Malignant melanoma arising in giant congenital nevus is a wel l known but rare event. Case report. A 15 day-old boy with giant congenital nevus all over the left leg was seen for a 6 mm red and bleeding nodule inside the nevus on the in ner thigh. Histopathology showed spindle cell malignant melanoma. A 3 cm ed ge surgical excision was performed with a favorable outcome which persists 5 years later. Discussion. The diagnosis of malignant melanoma is always very difficult in a child, unless metastasis occurs. Histopathologic modifications of childh ood malignant melanomas are discussed. Development of malignant melanoma in giant congenital nevus would not appear to exceed 5 p. 100. Nevertheless, early surgical excision is recommended because the nevus is smaller and ski n mobilization is easier at this age.