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Case Report
A case of low-grade appendiceal mucinous neoplasm with infection treated with ileal resection
1 MD, Gastrointestinal Surgery Registrar, Department of Surgery, Chugokurosai Hospital, Hiroshima, Japan; Department of Gastroenterological and Transplant Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
2 MD, PhD, Gastrointestinal Surgery Attending, Department of Surgery, Chugokurosai Hospital, Hiroshima, Japan
3 MD, PhD, Pathology Attending, Department of Pathology, Chugokurosai Hospital, Hiroshima, Japan
4 MD, PhD, Gastrointestinal Surgery Attending, Department of Gastroenterological and Transplant Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
Address correspondence to:
Shoichiro Mukai
Department of Surgery, Chugokurosai Hospital, 1-5-1, Hirotagaya, Kure City, Hiroshima 737-0193,
Japan
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Article ID: 100162Z12AO2025
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Okada A, Mukai S, Nishida T, Fukuda T, Ohdan H. A case of low-grade appendiceal mucinous neoplasm with infection treated with ileal resection. J Case Rep Images Surg 2025;11(2):19–23.ABSTRACT
Introduction: Low-grade appendiceal mucinous neoplasm (LAMN) is a rare tumor found in only 0.27% of appendectomy specimens. It is often misdiagnosed as appendicitis, and patients can remain asymptomatic for years, delaying treatment. This report describes a rare case of LAMN with infection that required surgery 14 years after its initial detection without treatment.
Case Report: A 54-year-old woman presented with right lower abdominal pain and fever for five days. Fourteen years earlier, a computed tomography (CT) scan revealed a cystic lesion in the appendix; however, no treatment was initiated. On admission, her temperature was 38.5 °C, with mild tenderness. Blood tests showed elevated C-reactive protein (CRP) levels, and CT imaging revealed a 9 cm inflamed cystic lesion. Antibiotics were ineffective, and the patient underwent an ileal resection. Laparotomic resection was selected due to the patient’s prior history of surgery, suspected adhesions secondary to inflammation, and the considerable tumor size. The tumor was removed intact. Histopathological analysis confirmed a LAMN with associated infection. The postoperative ileus was treated with decompression, and the patient was discharged on day 20.
Conclusion: When a LAMN is removed without perforation, the risk of recurrence is minimal, and the prognosis is excellent. Therefore, early diagnosis and resection are essential. Careful surgical planning is critical to prevent tumor rupture and complications such as pseudomyxoma peritonei (PMP). This case emphasizes the importance of timely intervention.
Keywords: Appendix, Ileal resection, Infectious disease, Low-grade appendiceal mucinous neoplasm
SUPPORTING INFORMATION
Author Contributions
Akifumi Okada - Substantial contributions to conception and design, Acquisition of data, Drafting the article, Final approval of the version to be published
Shoichiro Mukai - Substantial contributions to conception and design, Revising it critically for important intellectual content, Final approval of the version to be published
Toshihiro Nishida - Interpretation of data, Revising it critically for important intellectual content, Final approval of the version to be published
Toshikatsu Fukuda - Substantial contributions to conception and design, Revising it critically for important intellectual content, Final approval of the version to be published
Hideki Ohdan - Substantial contributions to conception and design, Revising it critically for important intellectual content, Final approval of the version to be published
AcknowledgmentsThe text was translated using the DeepL.com software
Guarantor of SubmissionThe corresponding author is the guarantor of submission.
Source of SupportNone
Consent StatementWritten informed consent was obtained from the patient for publication of this article.
Data AvailabilityAll relevant data are within the paper and its Supporting Information files.
Conflict of InterestAuthors declare no conflict of interest.
Copyright© 2025 Akifumi Okada et al. This article is distributed under the terms of Creative Commons Attribution License which permits unrestricted use, distribution and reproduction in any medium provided the original author(s) and original publisher are properly credited. Please see the copyright policy on the journal website for more information.
