Certain persons, especially in childhood or youth, are prone to repeated subacute inflammations of the tonsils, and as these recur the tonsils acquire a permanent enlargement. This consists anatomically in a true hypertrophy of the lymphatic follicles, although there is sometimes also an increase of the interstitial connective tissue. The tonsils are rarely much indurated, the soft lymphatic tissue existing so abundantly as to make the structure as a whole somewhat soft. The enlargement is very variable, there being sometimes a rapid enlargement followed by a rapid subsidence.

The inflammation sometimes leaves behind deep pits and recesses in the tonsils. These may contain semi-solid plugs, consisting of the secretions of the mouth mixed with particles of food, microbes, and fungi. These sometimes become condensed into concretions (Calculi in tonsils). The contents of these exaggerated crypts, by reason of their decomposition, often irritate the tissue around.

The hypertrophy is not always the result of chronic inflammation. There are cases of congenital hypertrophy of the tonsils, and there are still more frequent cases of a gradual enlargement without any apparent attacks of inflammation. In this way the tonsils may acquire very large dimensions, reaching the size of a hen's egg on some occasions. These conditions also are met with chiefly in children.

In children it is common to have an enlargement of the closed lymphatic follicles of the pharynx, and especially of the naso-pharynx, having similar characters to the enlargement of the tonsils which is so frequent in children. To this condition the somewhat misleading term Adenoid growths is given. The structure is that of lymphatic tissue, and the condition is an enlargement from chronic inflammation. In prolonged cases there may be an induration of the structures from connective-tissue formation.