High-grade appendiceal mucinous neoplasm: case report

Arrieta Navarro J.C.; Leiva Valderrama J.E.; Coral Salvador S.D.; Escudero Navarro N.K.; Silva Amaya A.H.; Aguilar Melin S.D. · Journal of Surgical Case Reports (2026) · DOI: 10.1093/jscr/rjag649

Resumen

High-grade appendiceal mucinous neoplasm is an extremely rare gastrointestinal tumour with nonspecific clinical manifestations that complicate preoperative diagnosis. In women, it may mimic gynecological diseases, particularly ovarian tumours, leading to diagnostic delays and inappropriate surgical approaches. We report the case of a 68-year-old woman from the San Martín region of Peru who presented with abdominal pain, progressive distension, and abnormal vaginal bleeding. Laboratory tests showed elevated carcinoembryonic antigen levels, while transvaginal ultrasound revealed a right adnexal mass suggestive of ovarian neoplasia. During surgery, a mucinous appendiceal mass without ovarian involvement was incidentally identified, prompting modification of the surgical plan to an oncological right hemicolectomy. Histopathological analysis confirmed high-grade mucinous adenocarcinoma of the appendix. The postoperative course was favorable. This case highlights the importance of considering appendiceal neoplasms in the differential diagnosis of pelvic masses in postmenopausal women and the value of intraoperative and histopathological evaluation. © The Author(s) 2026. Published by Oxford University Press and JSCR Publishing Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

Instituciones: Universidad Nacional de San Martín