Waldeyer’s ring consists of submucosal and subepithelial lymphatic tissues localised in the region of the pharynx. The distinct structures of Waldeyer’s ring comprise the tubal, pharyngeal, palatine, and lingual tonsils (fig 1). The pharyngeal tonsils, also know as adenoids, consist of a single pyramidal mass of lymphatic tissue, located at the posterior superior nasopharynx. The surface is folded with no true crypts.1
Palatine tonsils, frequently referred to as the tonsils, are bilateral structures situated in the tonsillar beds. Palatine tonsils consist of 10–30 crypts, lined by the surface epithelium. The lingual tonsils are an aggregation of lymphatic tissue located in the lamina propria of the root of the tongue. There is only one crypt for each nodule in the lingual tonsils.1
The localisation of the tonsils.
Pharyngeal, palatine, and lingual tonsils form part of the secondary immune system. They are exposed to ingested or inspired antigens that pass through the epithelial layers. The immunological structure is divided into four compartments: reticular crypt epithelium, extrafollicular area, mantel zone of the lymphoid follicle, and the germinal centre of the lymphoid follicles. The epithelium overlying the lymphatic tissues in the tonsil crypts is of the squamous cell type. As usual, antigens are presented to T helper cells, thereby inducing a B cell response in the germinal centre, which results in antibody production. Secretory IgA is the main antibody produced in the tonsils.
Several microbial organisms can infect the tonsils, the best known agents being Epstein-Barr virus, adenoviruses, influenza A and B viruses, herpes simplex virus, respiratory syncytial virus, and parainfluenza virus.2
During the past 10 years, increasing evidence has suggested that human papillomaviruses (HPVs) can also infect the tonsillar epithelium.3,4
Similar to other mucosal sites, HPV infections have been associated with malignant transformation in this anatomical region.3–9
However, there is much confusion in the literature regarding HPV infections in head and neck cancers. Head and neck cancer includes cancer of the lip, the oral cavity, the nose and sinuses (sinonasal cancer), the nasopharynx, the oropharynx, the hypopharynx, the larynx, the oesophagus, and the salivary glands, in addition to the soft tissues of the neck and ear (fig 1). Thus, the detection rates of HPV reported in head and neck cancer do not provide us with a detailed view on the association with HPV in the distinct entities, unless their detailed anatomical locations are given.
“There is much confusion in the literature regarding human papillomavirus infections in head and neck cancers”
When studying the literature, even non-epithelial tumours, such as lymphomas and sarcomas, are often included among head and neck cancers in these reports. Consequently, assessment of the real detection rates of HPV DNA in tonsillar carcinomas is laborious, necessitating the scrutiny of the tables of all individual studies reporting on both head and neck cancers and cancers of the upper aerodigestive tract. In this review, these reports will be summarised by grouping the lesions according to their accurate anatomical location (whenever possible), to give the reader a more organised view on these complex data.