Incidental presentation of appendix neuroendocrine tumor: Long-term results from a single institution.

Background: Appendix neuroendocrine tumors (NETs) are the most common tumors of the appendix and are most often diagnosed incidentally. The aim of this study was to retrospectively evaluate appendix NETs diagnosed incidentally in our clinic.

Methods: Of 8304 patients who underwent appendectomy with the diagnosis of acute appendicitis in Ankara Training and Re-search Hospital, General Surgery Clinic between January 2009 and January 2022, 33 had histopathology results evaluated as appendix NET, and a retrospective analysis was made of these cases. The patients were evaluated in terms of age, gender, tumor infiltration, tumor location, tumor size, surgical margin, tumor World Health Organization grade, surgery performed, lymph node metastasis, Ki67 index, number of mitosis, follow-up time, and survival.

Results: The rate of appendix NET was found to be 0.4%. The 33 cases comprised 15 (45.5%) males and 18 (54.5%) females with a mean age of 35.48 years (range: 16-84 years). Positive surgical margin was determined in 1 (3.03%) case, in which right hemicolectomy was performed. All other cases were followed up after appendectomy. The median follow-up was 89 (7-145) months. No recurrence was observed in any case. Mortality developed during follow-up in one case due to non-tumoral causes.

Conclusion: Appendix NETs are generally asymptomatic and appear incidentally after appendectomy due to acute appendicitis. Appendix NETs diagnosed incidentally are generally below 2 cm and have a good prognosis.