Incidental appendiceal neoplasms in patients undergoing appendectomy for acute appendicitis: a 10-year retrospective analysis of 5001 cases.

BACKGROUND

Appendiceal neoplasms are rare clinical entities often diagnosed incidentally during surgery for acute appendicitis. This study aims to investigate the incidence, histopathological diversity, and clinical characteristics of appendiceal neoplasms detected in patients undergoing appendectomy.

METHODS

We retrospectively analyzed the medical records and histopathological reports of 5001 patients who underwent appendectomy between January 2016 and December 2025 at a single tertiary center. Patient demographics, preoperative imaging findings, intraoperative observations, and detailed histopathological parameters (tumor type, grade, size, and margin status) were evaluated.

RESULTS

Appendiceal neoplasms were identified in 63 patients (1.26%). The mean age was 52.8 ± 18.2 years. The histological distribution included appendiceal neuroendocrine tumors (ANETs; 52.4%), appendiceal mucinous neoplasms (AMNs; 34.9%), adenocarcinomas (4.8%), goblet cell adenocarcinomas (4.8%), and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs; 3.2%). Preoperative radiological suspicion was present in only 11.1% of cases, while intraoperative macroscopic suspicion was noted in 14.3%. Complicated appendicitis was observed in 20.6% of neoplastic cases. Positive surgical margins were detected in 17.5% of the total cohort, reaching 22.7% in the AMN subgroup.

CONCLUSIONS

Appendiceal neoplasms frequently present as acute appendicitis and are largely undetectable by preoperative imaging or intraoperative assessment. Given the significant incidence of incidental malignancies, routine histopathological examination of all appendectomy specimens is mandatory for accurate diagnosis and the initiation of appropriate multidisciplinary management.