The adenoid, also known as a pharyngeal tonsil or nasopharyngeal tonsil, is the superior-most of the tonsils.It is a mass of lymphatic tissue located behind the nasal cavity, in the roof of the nasopharynx, where the nose blends into the throat.In children, it normally forms a soft mound in the roof and back wall of the nasopharynx, just above and behind the uvula.