Pigmented lesions in the newborn

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Melanocytic Naevus

Congenital melanocytic naevi are divided into categories depending on their size.

Small naevi are lesions under 20 mm in diameter. They are common, occurring in about 1% of newborns. One or more lesion may be noted in the newborn. Intermediate naevi are between 2 and 20 cm as in the accompanying photograph. The third category of giant naevi is discussed below.

Intermediate naevi carry a risk of undergoing malignant change usually after puberty, although rarely before. Removal in early childhood is advocated.

Small congenital naevi have a small potential for malignant melanoma and very rarely undergo malignant change before puberty. Some dermatologists advocate their removal as well, others advocate instructing the parents on malignancy signs and the need to pass this information to the child later on and adopting a watchful approach. Others advocate removal of small naevi located at "difficult to monitor" sites such as in the scalp or back.

Bathing trunk naevus

This infant has a couple of small naevi on the face and the left flank.

However, turning the baby over reveals a large melanocytic nevus extending over a wide area of the trunk. There is a significant risk of eventual development of malignant melanoma in such lesions so that surgical excision is recommended.

Early plastic surgical involvement in the management of such infants is required. There is also a risk of meningeal involvement so that ongoing Paediatric follow up is also required.