Endometriosis of the appendix: prevalence, associated lesions, and proposal of pathogenetic hypotheses. A retrospective cohort study with prospectively collected data

Objective To assess the prevalence of endometriosis of the appendix and the association with other pelvic localizations of the disease and to provide pathogenesis hypotheses.

Monocentric, observational, retrospective, cohort study. Patients undergoing laparoscopic endometriosis surgery in our tertiary referral center were consecutively enrolled. The prevalence of the different localizations of pelvic endometriosis including appendix involvement detected during surgery was collected. Included patients were divided into two groups based on the presence of appendiceal endometriosis. Women with a history of appendectomy were excluded. Measurements and main results. Four hundred-sixty patients were included for data analysis. The prevalence of appendiceal endometriosis was 2.8%. In patients affected by endometriosis of the appendix, concomitant ovarian and/or bladder endometriosis were more frequently encountered, with prevalence of 53.9% (vs 21.0% in non-appendiceal endometriosis group, p = 0.005) and 38.4% (vs 11.4%, p = 0.003), respectively. Isolated ovarian endometriosis was significantly associated to appendiceal disease compared to isolated uterosacral ligament (USL) endometriosis or USL and ovarian endometriosis combined (46.2% vs 15.4% vs 7.7%, p < 0.001). Poisson regression analysis revealed a 4.1-fold and 4.4-fold higher risk of ovarian and bladder endometriosis, respectively, and a 0.1-fold risk of concomitant USL endometriosis in patients with appendiceal involvement.

Involvement of the appendix is not uncommon among patients undergoing endometriosis surgery. Significant association was detected between appendiceal, ovarian, and bladder endometriosis that may be explained by disease dissemination coming from endometrioma fluid shedding. Given the prevalence of appendiceal involvement, counseling regarding the potential need for appendectomy during endometriosis surgery should be considered. Similar content being viewed by others Data availability The data underlying this article cannot be shared publicly due to the need for privacy of individuals that participated in the study. The data will be shared on reasonable request to the corresponding author.

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F.F.: Conceptualization, Supervision, Validation, Writing—review & editing. M.P.: Data curation, Investigation, Formal Analysis, Software. F.G.M.: Conceptualization, Investigation, Project Administration, Supervision, Validation, Visualization, Writing—review & editing. E.Z.: Conceptualization, Data curation, Investigation, Methodology, Visualization, Writing—original draft; Writing—review & editing. L.L.: Conceptualization, Investigation, Methodology, Project administration, Supervision, Validation, Writing—original draft. Corresponding author Ethics declarations Conflict of interest The authors have no conflicts of interest. Additional information Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Supplementary Information Below is the link to the electronic supplementary material. Rights and permissions Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law. About this article Cite this article Centini, G., Ginetti, A., Colombi, I. et al. Endometriosis of the appendix: prevalence, associated lesions, and proposal of pathogenetic hypotheses. A retrospective cohort study with prospectively collected data. Arch Gynecol Obstet 310, 1669–1675 (2024). https://doi.org/10.1007/s00404-024-07650-8 Received: Accepted: Published: Version of record: Issue date: DOI: https://doi.org/10.1007/s00404-024-07650-8