Skin lesions like nevus (mole) of any type can turn cancerous very late in life. These are very easy to observe day to day and one need not be rushing to surgery in childhood. Only after puberty would the abnormalities stabilize and skin layers would develop fully. These should generally be protected from sun rays. most dermatologists recommend sebaceous naevi be excised when the patient is a teenager or in early adult life.
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Outlook is good if there are no associated eye, skeletal or brain problems.