Lou YM, Gao TZ, Zheng CZ, Yu H, Hong YY, Liu XS. Microscopic evaluation of giant peritoneal loose body: A case report. World J Gastrointest Surg 2026; 18(9): 121842 [DOI: 10.4240/wjgs.121842]
Corresponding Author of This Article
Xiao-Sun Liu, Professor, Department of Gastrointestinal Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, No. 366 Wutong Road, Hangzhou 310000, Zhejiang Province, China. xiaosunliu@zju.edu.cn
Research Domain of This Article
Gastroenterology & Hepatology
Article-Type of This Article
case-report
Open-Access Policy of This Article
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World J Gastrointest Surg. Sep 27, 2026; 18(9): 121842 Published online Sep 27, 2026. doi: 10.4240/wjgs.121842
Microscopic evaluation of giant peritoneal loose body: A case report
Yu-Ming Lou, Tian-Zhe Gao, Chao-Ze Zheng, Hang Yu, Yan-Yun Hong, Xiao-Sun Liu
Yu-Ming Lou, Tian-Zhe Gao, Chao-Ze Zheng, Hang Yu, Yan-Yun Hong, Xiao-Sun Liu, Department of Gastrointestinal Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310000, Zhejiang Province, China
Author contributions: Liu XS cared for the patient; Lou YM and Liu XS collected the patient data and drafted and edited the manuscript; Gao TZ and Zheng CZ collected patient data; Yu H and Hong YY provided critical comments regarding the manuscript; all authors have read and approved the final manuscript.
AI contribution statement: AI tools (specifically DeepSeek) were used solely for linguistic refinement and formatting assistance. No AI tool was involved in the generation of research data, interpretation of results, or formulation of conclusions. All AI-generated outputs were critically reviewed and revised by the authors.
Supported by The Joint TCM Science & Technology Projects of National Demonstration Zones for Comprehensive TCM Reform, No. ZY-KJS-ZJ-2025-052.
Informed consent statement: Informed written consent was obtained from the patient for publication of this report and any accompanying images.
Conflict-of-interest statement: The authors declare no competing interests.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Corresponding author: Xiao-Sun Liu, Professor, Department of Gastrointestinal Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, No. 366 Wutong Road, Hangzhou 310000, Zhejiang Province, China. xiaosunliu@zju.edu.cn
Received: April 2, 2026 Revised: June 1, 2026 Accepted: July 16, 2026 Published online: September 27, 2026 Processing time: 166 Days and 3.2 Hours
Abstract
BACKGROUND
Giant peritoneal loose body (PLB) occurs in the abdominal or pelvic cavity. It is rare and the causes of its occurrence are unclear. Here, we report a case of giant PLB and further reveal the related metabolic products and microorganisms within it.
CASE SUMMARY
A 74-year-old man presented with lower back discomfort for two weeks. Abdominal computed tomography revealed a large, well-circumscribed solid mass at the left pelvic margin. The symptoms improved after surgical removal. A giant PLB with central calcification and necrotic adipose tissue was identified by pathological investigation. While metabolomic profiling showed an enrichment of arachidonic acid (AA) and palmitoylethanolamide (PEA), additional metagenomic analysis confirmed the presence of Aspergillus, Acinetobacter and Aeromonas.
CONCLUSION
Fat necrosis and microbial stimulation in patients with intestinal inflammation, surgery or trauma, and AA/PEA imbalance may result in giant PLB formation.
Core Tip: An instance of a giant peritoneal loose body (PLB) is described. We, for the first time, examined the interior microbial composition and metabolite profile using metagenomic sequencing and liquid chromatography–mass spectrometry. Arachidonic acid and palmitoylethanolamide, the two lipid bioactive mediators, were found along with microorganisms such as Aspergillus, Acinetobacter and Aeromonas. We speculate that continuous stimulation by fat necrosis and microorganisms on abdominal macrophages may be the fundamental cause of giant PLB formation.
