RETICULAR EPITHELIUM AND UNDERLYING HIGH ENDOTHELIAL VENULES OF HUMAN NASOPHARYNGEAL AND PALATINE TONSILS: A COMPARATIVE HISTOLOGICAL STUDY

Abstract

Background: The tonsils are important structures for immunological functions and are composed of nasopharyngeal and palatine tonsils. They bear varying degrees of antigenic insult.

Objective: To compare the reticular epithelium and underlying high endothelial venules of human nasopharyngeal and palatine tonsils.

Material and Methods: This was a comparative cross-sectional study conducted in the Anatomy Department of CPSP Regional Centre, Islamabad, Pakistan from January to December 2005. Thirty samples each of human nasopharyngeal, right palatine, and left palatine tonsils were collected by convenience sampling technique. Haematoxylin and eosin stained paraffin sections were examined for patches of reticular epithelium. Distance between the patches was measured and high endothelial venules in the subepithelial compartments were counted.

Results: The reticular epithelium had the same structure in both tonsils. The distance between two patches was 181.18 ± 17.83 µm in nasopharyngeal and 726.01 ± 48.89 µm in palatine tonsils. Comparison showed a significant statistical difference (P = 0.000). The mean counts of high endothelial venules in lymphoid compartments beneath these patches were 2.19 ± 0.1 and 1.85 ± 0.12 respectively, without significant statistical difference (P = 0.75).

Conclusion: Although the degree of reactivity of reticular epithelium in both types of tonsils might be similar, the nasopharyngeal tonsil may react to antigenic stimulus more rapidly compared to palatine tonsil due to more frequent reticulation of epithelium on the mucosal surface.