Tonsils and adenoids are congenital structures similar to glands elsewhere in the body. Tonsil is a round, porous tissue at the back of the throat and its size varies from person to person. Adenoids are structures located behind the nose, above the level of the soft palate and cannot be seen from inside the mouth. Tonsils and adenoids constitute the first step of the immune system in the body. They play an important role in creating resistance against these microorganisms in the immune system by sampling viruses and bacteria that enter the body through the nose and throat. However, sometimes they themselves become infected.