Uncommon causes of acute appendicitis: Retrospective analysis of 6785 histopathological findings in a tertiary center.

Background: This study aims to determine the uncommon causes of acute appendicitis in analyzed post appendectomy specimens.
Methods: Histopathology reports of 6785 removed appendices were analyzed retrospectively in order to confirm the uncommon cause of acute appendicitis in single tertiary institution.
Results: Unusual cause of acute appendicitis was found in 98 (1.44%) samples (40 female and rest 58 male patients). Neuroen-docrine tumor of the appendix was the most common pathology, followed by serrated adenoma, low-grade appendicular mucinous neoplasm, hyperplastic polyp, and intestinal parasite. In four patients (0.05%), appendicular adenocarcinoma was confirmed with an overall mortality of 75%. Age was significantly higher in uncommon acute appendectomies than in ordinary appendectomies. Survival analysis of unusual appendectomies showed that advanced age is of prognostic importance (Kaplan Meier p<0.0001). There was also a difference in survival between different disease groups in unusual appendectomies, but Cox multifactorial analysis showed that these two factors were not statistically significant.
Conclusion: Although rare, unusual causes are the etiological factor responsible for acute appendicitis. These reasons should be kept in mind in the older age group and the diagnosis of appendicitis should be made carefully.