Adenoiditis is the inflammation of the adenoid tissue, usually caused by an infection.

Children with obstructive sleep apnea typically have enlarged tonsils and adenoid tissue.

Incidence decreases with age, with adenoiditis being rare in children over 15 years due to physiological atrophy of the adenoid tissue.

Beneath the mucous membrane on the oral surface of the soft palate is a considerable amount of adenoid tissue.

The altered coat of the arterioles, consisting of adenoid tissue, presents here and there thickenings of a spheroidal shape, the white pulp.

They are merely local expansions or hyperplasia of the adenoid tissue, of which the external coat of the smaller arteries of the spleen is formed.

It is currently believed that bacterial biofilms play an integral role in the harboring of chronic infection by tonsil and adenoid tissue so contributing to recurrent sinusitis and recurrent or persistent ear disease.

Their trabecular sheaths gradually undergo a transformation, become much thickened, and converted into adenoid tissue; the bundles of connective tissue becoming looser and their fibrils more delicate, and containing in their interstices an abundance of lymph corpuscles.

Beneath the epithelium and its basement membrane is a fibrous layer infiltrated with lymph corpuscles, so as to form in many parts a diffuse adenoid tissue, and under this a nearly continuous layer of small and larger glands, some mucous and some serous, the ducts of which open upon the surface.