Congenital nevushttps://en.wikipedia.org/wiki/Congenital_melanocytic_nevus
Congenital nevus is a type of melanocytic nevus found in infants at birth. This type of birthmark occurs in an estimated 1% of infants worldwide.

As compared with a melanocytic nevus, congenital melanocytic nevi are usually larger in diameter and may have excess hair. If over 40 cm (16 in) with hypertrichosis, it is sometimes called giant hairy nevus.

Melanocytic nevi often grow proportionally to the body size as the child matures. Prominent hairs often form, especially after puberty.

Surgical excision is the standard of care. Many are surgically removed for aesthetics. But, larger ones are excised for prevention of cancer. Giant congenital nevi are at higher risk for malignancy degeneration into melanoma. Estimates of transformation into melanoma vary from 2-42% in the literature.

When the lesion is small, it can be surgically removed. But, it is very difficult to remove it completely without scar when it becomes large with age.

○ Treatment
#Staged excision (congenital nevus)
  • It is difficult to completely remove large nevi on the nose if they are not removed in the neonatal period.
  • Congenital nevus (typical case) ― It starts with small dots in the neonatal period, but it grows larger over time. From a cosmetic point of view, it is better to remove it when it is small.
  • In cases of wide involvement, there is a high probability of developing skin cancer in the future.
  • Since it has an irregular shape, a biopsy is necessary.
References Effective Treatment of Congenital Melanocytic Nevus and Nevus Sebaceous Using the Pinhole Method with the Erbium-Doped Yttrium Aluminium Garnet Laser 25324667 
NIH
Congenital melanocytic nevus (CMN) is a melanocytic nevus that is either present at birth or appears during the latter stages of infancy. Nevus sebaceous has been described as the hamartomatous locus of an embryologically defective pilosebaceous unit. Here, we describe how we used the pinhole technique with an erbium-doped yttrium aluminium garnet (erbium : YAG) laser to treat nevi lesions in different patients.
 Giant congenital melanocytic nevus 24474093 
NIH
Giant congenital melanocytic nevus is usually defined as a melanocytic lesion present at birth that will reach a diameter ≥ 20 cm in adulthood. Its incidence is estimated in <1:20,000 newborns. Despite its rarity, this lesion is important because it may associate with severe complications such as malignant melanoma, affect the central nervous system (neurocutaneous melanosis). The estimated lifetime risk of developing melanoma varies from 5 to 10%.