Moles or nevus

Congenital moles or nevi are a type of pigmentary skin lesion that appears at birth. They are relatively frequent and produce a significant cosmetic defect in some cases. Depending on their size, they can increase the risk of melanoma in adulthood.

Causes

Nevi are made up of clumps of skin cells. In the case of moles or melanocytic nevi, these cells are melanocytes. Melanocytic nevi can be congenital or acquired. A congenital melanocytic nevus appears in 1% of newborns. They are classified into three types:

• Small: they are the most frequent and measure less than 1.5 cm in diameter.
• Medium: they measure between 1.5-20 cm in diameter.
• Giants: more than 20 cm in diameter.

Symptoms

Small and medium-sized nevi can have a very varied appearance: from a small spot to a raised, dark brown lesion. They are located preferably in the abdomen,

shoulders and limbs. Giant nevi can be covered with hair and can cover entire areas of the trunk or a complete limb. Pigmentation can be uneven, acquiring different shades of brown. The surface can become rough.

The risk of malignancy (of developing a melanoma in the future) depends on the size. Small nevi are infrequently malignant. Only the giants are at high risk of developing skin cancer.

Treatment

The goal of treatment is to reduce the risk of developing skin cancer and, secondly, to improve the child's aesthetic appearance. With small nevi, regular monitoring is recommended to check for changes in color or appearance or if it grows (signs of possible malignancy).

In medium nevi, a biopsy of a part of them is recommended to see what their internal structure is like; if they are superficial, the risk of malignancy is low and they are not removed. If, on the contrary, they are deep nevi, there is a greater risk of malignanting and they are removed by surgery. In giant nevi, treatment is more complicated due to the large affected area. They should be resected early and the skin repaired through grafts.