Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Peutz-Jeghers syndrome ?
    ### Response:
    Peutz-Jeghers syndrome is characterized by the development of noncancerous growths called hamartomatous polyps in the gastrointestinal tract (particularly the stomach and intestines) and a greatly increased risk of developing certain types of cancer.  Children with Peutz-Jeghers syndrome often develop small, dark-colored spots on the lips, around and inside the mouth, near the eyes and nostrils, and around the anus.
    