Age Modifies Only the Epithelial and Stromal Components of the Chronic Tonsillitis Lesion: A Morphometric Study of Human Palatine Tonsils from 4 to 40 Years

Background/Objectives: The palatine tonsil changes with age and with chronic inflammation, and morphometric studies rarely separate the two. We asked whether the normal tonsil changes between 4 and 40 years and whether all components of the chronic tonsillitis lesion develop on the same time course. Methods: Twelve morphometric parameters were measured on hematoxylin and eosin and Masson trichrome sections of 340 palatine tonsils from patients of both sexes aged 4 to 40 years: histologically normal tonsils removed at surgery for benign non-inflammatory oropharyngeal lesions (n = 160) and tonsils removed for chronic tonsillitis (n = 180). The effect of age was tested by one-way analysis of variance across six age periods, separately within each group, and each parameter was expressed as a ratio of diseased to normal tissue within the same age period. Results: In normal tonsils no parameter varied with age (all p > 0.05). In chronic tonsillitis, epithelial thickness, epithelial erosion, stromal fibrosis and the composite tissue inflammatory index varied with age after correction for twelve tests (F = 17.56 to 36.50; all p < 0.001). Crypt depth (4.8 to 5.5 times normal), capsular thickness (3.4 to 3.7 times), cryptal detritus and the follicular parameters kept the same ratio from 4 to 7 years to 36 to 40 years. Erosion, fibrosis and the inflammatory index were close to normal at 4 to 7 years and diverged from 8 to 12 years onward. Conclusions: The lesion of chronic tonsillitis has two components with different kinetics: remodeling of the crypt and follicle apparatus that is complete in early childhood, and epithelial and stromal damage that accumulates later, consistent with repeated cycles of injury and repair. Cryptal, capsular and follicular measurements can be compared across ages, whereas epithelial and stromal measurements need age-specific reference values.