Mast cells arise from the hemopoietic progenitor cells of the bone marrow derived and were first discovered by Paul Ehrlich in 18th century. They are found in varying numbers in different tissues and are abundant near blood vessels, nerves and in subepithelial tissues. They are constantly present in appendix, the organ most commonly subjected for surgical intervention and removal. The present study was undertaken 1) To compare the mast cell counts in the mucosa, sub mucosa and the muscular layers of the appendix. 2) To compare the mast cell counts in the normal appendix and in the acute, recurrent, and chronic appendicitis in various age groups. Materials and Methods: seven hundred and seventy-seven cases of appendix were evaluated for histopathological changes and number of mast cells in each layer. The mast cell count in various histopathological group were compared using ANOVA (DUNNETT) Test. The degree of mast cell density was evaluated using Pearson’s correlation test. Result: A higher mast cell count was seen in acute eosinophilic appendicitis and recurrent appendicitis. Mean mast cell counts were high in recurrent appendicitis with fibrosis, when compared with no fibrosis. Conclusion: Mast cell activation is one of the important factors in causation of appendicitis and thus this activation of mast cells backs the allergic theory of appendicitis.

Keywords: Mast cells; Appendix; Appendicectomy.