Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Giant congenital nevus ?
    ### Response:
    A giant congenital nevus is a dark-colored, often hairy patch of skin that is present at birth (congenital). It grows proportionally to the child. A congenital pigmented nevus is considered giant if by adulthood it is larger than 20cm (about 8 inches) in diameter.
    