Congenital melanocytic naevus

**Definition:** Congenital melanocytic naevi are circumscribed areas of skin pigmentation present at birth as a result of abnormal intrauterine proliferation of melanocytes within the dermis, the epidermis or both. They may range in size from a few millimetres to many centimetres in diameter. If their projected or final adult maximal diameter is greater than 20 cm they are termed giant congenital melanocytic naevi.