According to MedlinePlus, children can develop mental or emotional problems due to their congenital nevi, particularly if they are large. Some of the melanocytes can form clusters around the tissues in the brain and spinal cord, causing headaches, vomiting, irritability, seizures, or brain tumors.
Although most melanocytes are harmless, giant nevus birthmarks over 20 centimeters have a higher risk for melanoma. According to a 2013 article in Anais Brasileiros de Dermatologia, between 5% and 10% of people with giant congenital melanocytic nevi could develop melanoma. That’s why it’s important to monitor and remove them if they change.
Removing a congenital nevus birthmark might require surgery, depending on the nature and size of the birthmark. According to the Children’s Hospital of Philadelphia, plastic surgery might be needed for some removals to take care of any scarring and to improve the skin’s appearance. Dermabrasion, chemical peels, and other methods of removing the melanocytes are also options. Even if the birthmark has been removed, people who’ve had a congenital nevus birthmark must continually have their skin checked for any possible malignancy to avoid melanoma.