Birthmarks

The most pigmented lesions are nevi, i.e. moles and depending on their size they are divided into small <1.5cm, medium size 1.5-9.9cm, large 10-19.9cm and giant >20cm. Congenital melanocytic nevi (CMN) are present in 0.6-6% of newborns with small and medium-sized ones being more common, while large and giant ones are extremely rare (1:20000 births appear large nevi and 1:500000 births appear giant nevi). In the great majority of them, they are present at birth or appear after a few weeks.

These are benign tumors of melanocytes, which, however, have some chances of transforming into malignant melanoma during the person’s lifetime. Statistically, for small moles this percentage is 1-5% while it increases depending on the size of the mole and reaches 6.5-12% for the giant ones. They appear as round or oval slightly raised plaques with a clear, smooth or irregular outline. Sometimes, their surface is hairy while they may appear anywhere.

Because of the possibility of future transformation, the congenital melanocytic nevi (CMN) are surgically removed if possible, otherwise they are closely mapped and monitored clinically and dermatoscopically for any changes in their characteristics beyond the normal increase in size as the child grows.

When there are more than six cafe au lait macules present at birth, a thorough investigation is needed. In this case, we need to exclude a genetic condition, the neurofibromatosis.

The non-pigmented spots that present at birth may also be a sign of another genetic disease, the nodular sclerosis. In the category of hyperpigmentation lesions that present at birth are Mongolian spots, a racial characteristic in infants of Asian, Indian, African or even Southern European origin. They have no clinical significance and usually disappear by adulthood.

The non-pigmented congenital lesions include hemangiomas and vinus malformation. Hemangiomas regress by the age of 5 and are present at birth. Vinus malformations never regress and increase progressively.

When we detect an hemangioma a US test should be performed for further hemangiomatous formations in the internal organs.