Abstract

In this study, we prospectively investigated the histopathological features of the removed appendix tissue in pediatric patients who were operated on with the preliminary diagnosis of appendicitis. A catarrhal appendicitis group (n=43), a phlegmonous appendicitis group (n=28), a gangrenous appendicitis group (n=19), a perforated appendicitis group (n=35), and an appendicitis +COVID-19 group (n=7) were formed. The control group consisted of 21 children. A section of each patient's appendix tissue from the part with the highest diameter was taken for histopathological examination. The sections were routinely stained with hematoxylin and eosin (H&E). The two pathologists evaluated all H&E sections in a light microscope. The evaluation results were analyzed statistically. No significant differences in age and gender were found between all groups. The results of neutrophil and lymphocyte counts in all tissue layers of all groups were significantly different. Neutrophil count in the mucosa and muscularis propria in the appendix tissues of the control group were found to be zero. Among all groups, the highest number of neutrophil counts in the mucosa and muscularis propria were found in the perforated group. Among all groups, the highest number of lymphocyte counts in mucosa and muscularis propria were found in the Covid-19 group. The mucosal erosion, intraluminal neutrophils, and reactive lymphoid hyperplasia were negative in all samples in the control group. Neutrophil accumulation in the mucosa and muscularis propria layers in appendix tissue together with other inflammation findings are important in the histopathological diagnosis of appendicitis. In patients with Covid-19 infection, appendicitis may occur, in which case, severe accumulation of lymphocytes appears in the mucosal layer in addition.

Key words: Pediatric appendicitis, histopathological features, COVID-19 pandemic