Unusual Histopathologic Findings in Appendectomy Specimens: A Retrospective Analysis

Appendicitis is one of the most common acute conditions of the abdomen. Although, lymphoid hyperplasia and fecalith are the most common etiologic factors, some unusual factors including intestinal worms and tumors have been identified. The aim of this study was to investigate the incidence and implications of unusual histopathologic findings among appendectomy specimens from patients with clinical impression of acute appendicitis. The clinicopathological data of 2757 patients who had undergone appendectomy for presumed acute appendicitis from January 2006 to November 2013 were retrospectively assessed. According to microscopic findings, the patients were classified into six groups: appendix vermiformis, suppurative appendicitis, phlegmonous appendicitis, gangrenous appendicitis, perforated appendicitis, and unusual histopathologic findings. A total of 2757 appendectomies were performed to treat patients with suspected acute appendicitis. The mean age of patients was 25.4 ± 11.8 years (range, 5-86) and 69.7% were male. There were 1608 suppurative appendicitis (58.3%), 855 appendix vermiform (31%), 99 gangrenous appendicitis (3.6%), 19 perforated appendicitis (0.7%), 19 phlegmonous appendicitis (0.7%), and 157 patients with unusual histopathologic findings (5.7%). The unusual histopathologic findings (n = 157) were contained fibrous obliterated appendix (80.2%), carcinoid tumor (7%), mucocele (3.8%), Enterobius vermicularis (3.8%), B-cell non-Hodgkin's lymphoma (B-NHL) (1.9%), eosinophilic infiltration (1.2%), and granulomatous infiltration (1.9%). Histopathologic findings of appendectomy specimens revealed 14 malignancies among 157 unusual findings (8.9%; 0.5% of all appendectomies) including carcinoid tumor (n = 11) and B-NHL (n = 3). Although unusual pathologic findings in appendectomy specimens are rare, histopathologic assessment will allow early diagnosis of many unusual diseases. Thus, even when the macroscopic appearance of appendectomy specimens is normal, all specimens should be subjected for routine histopathologic examination.