A 19-year-old girl addressed an oncologist with complaints of slowly growing tumor-like mass on the tip of her tongue. The mass was first noticed 5-6 years ago. The patient requested no medical help. Objectively: there is a pale pink round growth with wide pedicle on the tongue apex; the growth is painless, elastic; there are no changes of mucosa surrounding the pedicle. Submandibular lymph nodes cannot be palpated. What kind of tumor is it?