CASE REPORT article
Front. Oncol.
Sec. Gastrointestinal Cancers: Colorectal Cancer
This article is part of the Research TopicAdvances in Gastrointestinal CancersView all 13 articles
Synchronous Primary High-Grade Appendiceal Mucinous Neoplasm (HAMN) and Ovarian Borderline Mucinous Cystadenoma: A Rare Case and Diagnostic Challenges
Provisionally accepted
- Liaoning Fangda General Hosipital, Shenyang, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Background: Appendiceal mucinous neoplasms (AMNs), particularly high-grade (HAMN) variants, are rare and pose significant diagnostic challenges. Their presentation can mimic other abdominal pathologies, and the occurrence of synchronous primary mucinous tumors of the appendix and ovary is an exceptionally rare phenomenon that is poorly described in the literature. Case Presentation: We report a case of a 59-year-old woman who presented with right lower quadrant pain and a palpable mass. Preoperative imaging identified a large, complex cystic mass suspicious for an ovarian primary. Tumor markers (CA19-9, CA125, CA15-3) were elevated. Colonoscopy revealed mucous discharge from the appendiceal orifice, shifting diagnostic suspicion. Exploratory laparotomy revealed a large appendiceal mass with cellular peritoneal mucinous deposits and involvement of the right adnexa. The patient underwent right hemicolectomy and bilateral salpingo-oophorectomy. Histopathological and immunohistochemical analysis confirmed a synchronous primary HAMN (CK20+, Villin+, CK7-) of the appendix and a primary borderline mucinous cystadenoma (CK7+, PAX-8+, CK20-) of the left ovary. Conclusion: This case underscores the diagnostic difficulty in distinguishing synchronous primary mucinous neoplasms from metastatic disease. A multidisciplinary approach, meticulous histopathological examination, and adjunctive immunohistochemistry are critical for accurate diagnosis and appropriate surgical management. This rare coexistence suggests the possibility of shared oncogenic pathways, warranting further investigation. Long-term surveillance is essential for these patients.
Keywords: Appendiceal mucinous neoplasm, High-grade appendiceal mucinous neoplasm (HAMN), Mucinous cystadenoma, Ovarian borderline tumor, Synchronoustumors
Received: 23 Oct 2025; Accepted: 16 Feb 2026.
Copyright: © 2026 Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yingyu Liu
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.