Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (683 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
A double-layered fold of peritoneum that attaches the stomach to other organs in the abdominal cavity.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Omentums.
Where it fits in the MeSH classification
- Broader topics
- Peritoneum
Related concepts
Research landscape
PubMed indexes 8,643 records tagged with the MeSH heading “Omentum” (counts retrieved 2026-10-31). 648 of them (7.5%) were published from 2020 onward, and the busiest period so far is through 1999 with 4,687 records.
Reviews account for 552 records (6.4%) and meta-analyses for 31. Randomized controlled trials number 53 (0.6%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 4,687 |
| 2000-2009 | 1,672 |
| 2010-2019 | 1,636 |
| 2020 onward | 648 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 552 | 6.4% |
| Meta-analyses | 31 | 0.4% |
| Randomized controlled trials | 53 | 0.6% |
Method: PubMed query "Omentum"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Stromal Cells Covering Omental Fat-Associated Lymphoid Clusters Trigger Formation of Neutrophil Aggregates to Capture Peritoneal Contaminants | 2020 | Research article Design not recorded in structured metadata | 82 | cc by PMID 32294409 · DOI · PMC7156918 |
| Protection from septic peritonitis by rapid neutrophil recruitment through omental high endothelial venules | 2016 | Research article Design not recorded in structured metadata | 72 | cc by PMID 26940548 · DOI · PMC4785224 |
| Milky spots: omental functional units and hotbeds for peritoneal cancer metastasis | 2016 | Review article Design not recorded in structured metadata | 71 | cc by PMID 26831659 · DOI · PMC4875158 |
| Harnessing lipid-driven immunometabolic pathways in omental metastases to enhance immunotherapy in patients with ovarian cancer | 2026 | Research article Design not recorded in structured metadata | 3 | cc by PMID 41775684 · DOI · PMC12957430 |
Stromal Cells Covering Omental Fat-Associated Lymphoid Clusters Trigger Formation of Neutrophil Aggregates to Capture Peritoneal Contaminants [1]
Abstract reading summary — source excerpts
- Opening excerpt
- The omentum is a visceral adipose tissue rich in fat-associated lymphoid clusters (FALCs) that collects peritoneal contaminants and provides a first layer of immunological defense within the abdomen.
- Closing excerpt
- Thus, specialized omental mesothelial cells coordinate the recruitment and aggregation of neutrophils to capture peritoneal contaminants.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (146 words)
The omentum is a visceral adipose tissue rich in fat-associated lymphoid clusters (FALCs) that collects peritoneal contaminants and provides a first layer of immunological defense within the abdomen. Here, we investigated the mechanisms that mediate the capture of peritoneal contaminants during peritonitis. Single-cell RNA sequencing and spatial analysis of omental stromal cells revealed that the surface of FALCs were covered by CXCL1+ mesothelial cells, which we termed FALC cover cells. Blockade of CXCL1 inhibited the recruitment and aggregation of neutrophils at FALCs during zymosan-induced peritonitis. Inhibition of protein arginine deiminase 4, an enzyme important for the release of neutrophil extracellular traps, abolished neutrophil aggregation and the capture of peritoneal contaminants by omental FALCs. Analysis of omental samples from patients with acute appendicitis confirmed neutrophil recruitment and bacterial capture at FALCs. Thus, specialized omental mesothelial cells coordinate the recruitment and aggregation of neutrophils to capture peritoneal contaminants.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 32294409 · DOI · PMC7156918
Protection from septic peritonitis by rapid neutrophil recruitment through omental high endothelial venules [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Acute peritonitis is a frequent medical condition that can trigger severe sepsis as a life-threatening complication.
- Closing excerpt
- This data identifies HEVs as a clinically relevant vascular recruitment site for neutrophils in acute peritonitis that is indispensable for host defence against early systemic bacterial spread and sepsis.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (152 words)
Acute peritonitis is a frequent medical condition that can trigger severe sepsis as a life-threatening complication. Neutrophils are first-responders in infection but recruitment mechanisms to the abdominal cavity remain poorly defined. Here, we demonstrate that high endothelial venules (HEVs) of the greater omentum constitute a main entry pathway in TNFα-, Escherichia coli (E. coli)- and caecal ligation and puncture-induced models of inflammation. Neutrophil transmigration across HEVs is faster than across conventional postcapillary venules and requires a unique set of adhesion receptors including peripheral node addressin, E-, L-selectin and Mac-1 but not P-selectin or LFA-1. Omental milky spots readily concentrate intra-abdominal E. coli where macrophages and recruited neutrophils collaborate in phagocytosis and killing. Inhibition of the omental neutrophil response exacerbates septic progression of peritonitis. This data identifies HEVs as a clinically relevant vascular recruitment site for neutrophils in acute peritonitis that is indispensable for host defence against early systemic bacterial spread and sepsis.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 26940548 · DOI · PMC4785224
Milky spots: omental functional units and hotbeds for peritoneal cancer metastasis [3]
Abstract reading summary — source excerpts
- Opening excerpt
- As the most common metastatic disease of abdomen pelvic cavity cancer, peritoneal carcinomatosis (PC) renders significant negative impact on patient survival and quality of life.
- Closing excerpt
- At last, the roles of MS in PC pathological process were summarized with special emphasis on the distinct roles of macrophages.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (170 words)
As the most common metastatic disease of abdomen pelvic cavity cancer, peritoneal carcinomatosis (PC) renders significant negative impact on patient survival and quality of life. Invasive peritoneal exfoliated cancer cells (PECCs) preferentially select the omentum as a predominant target site for cancer cell colonization and proliferation compared with other tissues in the abdominal cavity. The precise pathogenic mechanism remains to be determined. As omental milky spots (MSs) are the major implantation site for malignant cells in peritoneal dissemination, researches on mechanisms of PC have been mainly focused on MS, primitive lymphoid tissues with unique structural features, and functional characteristics. To date, extensive biophysical and biochemical methods have been manipulated to investigate the MS exact function in the peritoneal cavity. This review summarized MS as hotbeds for PECC. The anatomical distribution was briefly described first. Then, MS histology was systematically reviewed, including morphological features, cellular constituents, and histological staining methods. At last, the roles of MS in PC pathological process were summarized with special emphasis on the distinct roles of macrophages.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 26831659 · DOI · PMC4875158
Harnessing lipid-driven immunometabolic pathways in omental metastases to enhance immunotherapy in patients with ovarian cancer [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Immunotherapy with immune checkpoint blockade (ICB) in epithelial ovarian carcinoma (EOC) shows limited clinical benefit only for a small subset of patients.
- Closing excerpt
- We propose a non-invasive radiomics and machine-learning-based analysis of imaging data to assess omental involvement for patient stratification.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (215 words)
Immunotherapy with immune checkpoint blockade (ICB) in epithelial ovarian carcinoma (EOC) shows limited clinical benefit only for a small subset of patients. Overall response rates are low, so that overcoming immunotherapy resistance and improved stratification are key. In this study, we investigated the immunometabolic landscape of EOC with a focus on omental metastases, identifying lipid-laden macrophages as central elements for actionable therapeutic vulnerabilities and giving rise to biomarkers for improved patient stratification. Using patient-derived explants, we demonstrated a functional dichotomy inside the typically lipid-rich microenvironment of omental metastases: augmented maintenance of effector T cell function, while lipid uptake and processing by tumor-associated macrophages (TAMs) induces oxidative stress-dependent signaling programs, which drive macrophage dysfunction and immune suppression. Pharmacological modulation of lipid-driven signaling pathways through CCR5 inhibition (inflammation modulation through maraviroc) or blockade of the lipid scavenger receptor CD36 reprograms TAMs, restores T cell activity, and enhances antitumor immune responses within lipid-rich tumor niches. Mechanistically, studies in humanized mouse models reveal that maraviroc-mediated CCR5 inhibition induces transcriptional programs associated with immune activation in stressed, lipid-laden human TAMs. Consistent with these mechanistic insights, we demonstrated that the specific immunometabolic niche in omental metastases is clinically associated with responsiveness to ICB. We propose a non-invasive radiomics and machine-learning-based analysis of imaging data to assess omental involvement for patient stratification.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41775684 · DOI · PMC12957430
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Cellular and molecular processes in ovarian cancer metastasis. A Review in the Theme: Cell and Molecular Processes in Cancer Metastasis [5]
- Research article Immunological Functions of the Omentum [6]
- Research article The greater omentum. Anatomy, embryology, and surgical applications [7]
- Research article Specialized immune responses in the peritoneal cavity and omentum [8]
- Research article The omentum: anatomical, metabolic, and surgical aspects [9]
- Research article Organotypic models of metastasis: A three-dimensional culture mimicking the human peritoneum and omentum for the study of the early steps of ovarian cancer metastasis [10]
References
- Jackson-Jones LH, Smith P, Portman JR, Magalhaes MS, Mylonas KJ, Vermeren MM, et al.. Stromal Cells Covering Omental Fat-Associated Lymphoid Clusters Trigger Formation of Neutrophil Aggregates to Capture Peritoneal Contaminants. . 2020. PMID 32294409 · DOI · PMC7156918
- Buscher K, Wang H, Zhang X, Striewski P, Wirth B, Saggu G, et al.. Protection from septic peritonitis by rapid neutrophil recruitment through omental high endothelial venules. . 2016. PMID 26940548 · DOI · PMC4785224
- Liu J, Geng X, Li Y. Milky spots: omental functional units and hotbeds for peritoneal cancer metastasis. . 2016. PMID 26831659 · DOI · PMC4875158
- Suarez-Carmona M, Hampel M, Zhang XW, Pöchmann A, Grauling-Halama SA, Valous NA, et al.. Harnessing lipid-driven immunometabolic pathways in omental metastases to enhance immunotherapy in patients with ovarian cancer. . 2026. PMID 41775684 · DOI · PMC12957430
- Yeung TL, Leung CS, Yip KP, Au Yeung CL, Wong ST, Mok SC. Cellular and molecular processes in ovarian cancer metastasis. A Review in the Theme: Cell and Molecular Processes in Cancer Metastasis. Am J Physiol Cell Physiol. 2015. PMID 26224579 · DOI · PMC4593771
- Meza-Perez S, Randall TD. Immunological Functions of the Omentum. Trends Immunol. 2017. PMID 28579319 · DOI · PMC5812451
- Liebermann-Meffert D. The greater omentum. Anatomy, embryology, and surgical applications. Surg Clin North Am. 2000. PMID 10685153 · DOI
- Liu M, Silva-Sanchez A, Randall TD, Meza-Perez S. Specialized immune responses in the peritoneal cavity and omentum. J Leukoc Biol. 2021. PMID 32881077 · DOI · PMC7921210
- Collins D, Hogan AM, O'Shea D, Winter DC. The omentum: anatomical, metabolic, and surgical aspects. J Gastrointest Surg. 2009. PMID 19291335 · DOI
- Kenny HA, Dogan S, Zillhardt M, K Mitra A, Yamada SD, Krausz T, et al.. Organotypic models of metastasis: A three-dimensional culture mimicking the human peritoneum and omentum for the study of the early steps of ovarian cancer metastasis. Cancer Treat Res. 2009. PMID 19763444 · DOI · PMC3651885
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.