Definition: Waldeyer’s ring is a complete ring of subepithelial lymphoid tissue comprising of the palatine tonsils, adenoids, lingual tonsils, tubal tonsils and the lateral pharyngeal bands.
Parts of the Waldeyer’s ring:
1) Palatine tonsil.
2) Nasopharyngeal tonsil (adenoids).
3) Lingual tonsil present on the posterior 1/3 of tongue.
4) Tubal tonsil near the Rosenmuller’s fossa.
5) Lateral pharyngeal bands.
Importance of Waldeyer’s Ring:
- It is an important part of mucosal associated lymphoid tissue (MALT) which processes antigen and presents it to T-helper cells and B-cells.
- This ring acts as a protective barrier for the lower respiratory tract.
- Waldeyer’s ring is constantly exposed to new antigenic stimuli.
- Production of Immunoglobulins: The tonsillar tissue produces IgG, IgA and IgD. These immunoglobulins are secreted into pharynx and their output is increased in response to a wide variety of inflammatory processes.
- The tissue of Waldeyer’s ring undergoes physiological hypertrophy during early childhood as the child is exposed to increasing number of antigenic stimuli.
- Next to the gastrointestinal tract, Waldeyer’s ring is a common localization for extranodal lymphomas. Waldeyer’s ring is considered for staging of malignant lymphomas according to the Ann Arbor classification.
Regression: This lymphoid tissue reaches its maximum size by 10 years of age and then gradually regresses.