The word “nevus” is a synonym for the word “mole”. However, an epidermal nevus is a special kind of mole that does not look like the typical small moles almost every person has.
Becker’s nevus is an uncommon (but not rare) benign skin lesion. “Nevus” is another word for a mole and as such this growth appears as a very large and irregularly shaped mole. Which can be present at birth but most appear in puberty.
Congenital is a word that means “present from birth” while a nevus is the medical term for a mole. Therefore, a congenital nevus is a mole that was present on the body from birth.