الملخص

Background:The tonsils are lymphoepithelial tissue, it contains specialized lymphoid functional compartments which include the lymphoid follicles, parafollicular areas, crypt epithelium and high endothelial venules, which together have an essential role in the immunological process. These compartments may be altered histomorphologically throughout life time underneath common pathological condition.    Aim:The aim of the current study is to evaluate special microstructural functional compartment changes as high endothelial venules, lymphoid follicles, interfollicular and connective tissue areas according to histopathological ground of the palatine tonsils. Methods:one hundred palatine tonsillar samples which were attained from patients suffering from chronic tonsillitis, recurrent tonsillitis and obstructive hypertrophic tonsils were admitted at Al-Jumhuri Teaching Hospital and Al-salaam teaching hospital in Mosul city during the period from February 2018 to February 2019. Age of patients ranged from  (2-40) years. Specimens of tissue were directly fixed in 10% formalin then processed. Paraffin sections of 4μm thickness were exposed to routine stain with hematoxylin and eosin, while the studied marker (CD34) was detected by immunohistochemical method using labelled streptavidin-biotin (LSAB/HRP) method. Results: The high endothelial venules found in the subepithelial compartments as well as with in the reticulated crypt epithelium were characterized by prominent nuclei of the endothelial cells with non-epithelial cells were found on the luminal side. The mean count of high endothelial venules was peak with statistically significant in recurrent tonsillitis and hypertrophic tonsil in both surface epithelium1.67±0.24, 0.78±0.22 and crypt epithelium1.89±0.31, 0.89±0.20 (p=0.046, p= 0.032) respectively. However the percentage of follicle area compartment in the tonsillar hypertrophic cases was greater than in other infectious tonsillar diseases (30.33%) respectively. Contradictory, the interfollicular and connective tissue areas reach their maximum in chronic tonsillitis. Conclusion:The high endothelial venules are dispersed throughout the surface in addition to crypt epithelial. Follicular area percentage in the hypertrophic tonsils is higher than that in the chronic and recurrent tonsillitis group, representing a hyperplastic state of lymphoid cells in the germinal centers. It can also explain the alteration in immune defense mechanism underlying these pathological conditions.