What Is Omentum Cancer

Get health & wellness advice into your inbox

Your privacy is important to us. Any information you provide to us via this website may be placed by us on servers. If you do not agree to these placements, please do not provide the information.

Best Milk Alternative

Omentum cancer is an extremely rare type of cancer that initially starts in the fatty tissue in the stomach, and then spreads to the organs in the abdomen. While receiving a diagnosis of omentum cancer is uncommon, other cancers have the potential to metastasize in the omentum.

What is the omentum?

The omentum is an adipose tissue layer (otherwise known as body fat) that surrounds the intraperitoneal organs.  It is composed of two layers of mesothelial cells. The omentum stores fat and plays a role in immune regulation and tissue regeneration.1 Its size varies from 300 grams to 2000 grams and it is located in front of the abdominal organs.

The key functions of the omentum consist of:

  1. Fat storage: The omentum has the ability to store lipids. However, this function makes it susceptible to becoming a potential source for metastatic tumour cells.
  2. Immune-regulation: The omentum consists of lymphoid aggregates known as milky spots (MS), which comprise 70% of macrophages, 10% B-lymphocytes, 10% T-lymphocytes, and the remainder being stromal and mast cells. The milky spots were first discovered by Ranvier, a French anatomist, in 1874 whilst studying rabbits.   Milky spots serve to identify and engage antigens and pathogens within the peritoneal cavity, thereby eliciting an immune response.1, 2

Understanding omental cancer

 Before delving into the specifics of omental cancer development, it's essential to grasp the concept of cancer itself. Cancer occurs when cells grow uncontrollably, multiplying and invading nearby tissues. Over time, it can spread to different body parts. It is important to note that cancer describes uncontrolled, not fast proliferation. When cells replicate, they can form a malignant tumour, which spreads and invades tissues away from its primary site. A benign tumour is the opposite of this, which remains in its primary location. This type of tumour is non-cancerous.3 The omentum is a crucial site for B-lymphocyte development essential in the adaptive immune response. Individuals with primary malignant tumours reportedly have a 6-month survival time.  The survival rate is very scarce due to poor understanding of the omentum. hence more research is required in this field. 

What is metastasis?

Metastasis is when the cancer spreads from the primary tumour to other sites in the body by breaking away from the rest of the tumour.  The cells will move into the circulation and enter a new environment.4

Types of omentum cancer

There are two main types of omental cancer: primary omental cancer and metastatic omental cancer. Primary omental cancers are tumours that are considered sporadic. They can present themselves as asymptomatic. Alternatively, if there are symptoms, they are usually nonspecific 5.   This type of omental cancer is extremely rare as it requires the manifestation of cancer of the omentum itself. However, the type of tumour that can occur in this category can be ovarian cancer. The second type of omental cancer is metastatic omental cancer, which is the spread of the tumour to other organs, including breast cancer, gastrointestinal cancers and endometrial cancer.  

Ovarian cancer

As previously mentioned, ovarian cancer can become a site for omentum cancer. It has a high mortality rate, being the fifth most common cause of death in women. Studies utilising a mouse model mimicking ovarian cancer have illustrated its propensity to metastasise to the omentum, revealing a significant proliferation of cells in this tissue They also found that the omental fat cells activated p38 and STAT3  pathways. P38 is part of the kinase family, a protein that regulates cellular processes such as cell growth, inflammation and cell differentiation 6.  Additionally, STAT3 is a pathway that is part of the cytoplasmic family, which regulates cell growth and division as well as apoptosis 7,8. The activation of these two pathways demonstrated the significance of the environment of the omentum ( adipocyte-rich) for initiating the growth of tumour cells.

Treatment for ovarian cancer varies, depending on the spread, location and size of the Tumour. The two main interventions to tackle ovarian cancer are surgery and chemotherapy. Surgery is an option for those with an early diagnosis, as the cancer will be localised in one location.  If other treatments prove ineffective, doctors can use radiotherapy. This treatment employs radiation to destroy cancer cells.9

Stomach cancer

 Stomach cancer is a type of gastrointestinal cancer that is the third leading cause of cancer deaths in the world. Stomach cancers are 90% sporadic, although 5-10% of cases stem from patients with a family history of gastric cancers. Other factors increase gastric cancers, such as diet and smoking. Helicobacter pylori ( H. pylori)  is a bacteria from the family Helicobacteraceae, which causes 60% of gastric ulcers and 90% of duodenal ulcers. Treatment for stomach cancer requires surgical interventions.  This treatment is specifically intended for patients diagnosed with localized gastric cancer, proving particularly effective in cases of early gastric cancer. However, there is a notable decline in the utilization of surgical intervention, with rates dropping by 35% for stage II and 25% for stage III, impacting the long-term survival rates, which stand at 10%.10

Omental tumours

The most common omental tumours are hemangiopericytomas, leiomyosarcoma, fibrosarcomas and liposarcomas. 

Hemangiopericytomas are tumours that derive from the pericytes. These tumours surround the blood vessels. As it is a rare type of tumour, the diagnosis and management of hemangiopericytoma are not well established.11 The symptoms vary in individuals, however, the most common symptoms reported are hypertension, hypoglycemia, and flank pain.12

Leiomyosarcoma is another rare cancer that targets muscles in the intestines, bladder, stomach and blood vessels. For women, leiomyosarcoma grows in the smooth muscle of the uterus.  Initially, there are no symptoms; however, as the tumour grows, the symptoms include weight loss, vomiting and pain.13

Fibrosarcoma can grow in the bone and soft tissue, more prevalent in middle-aged and older adults.14  

Liposarcomas derive from the lipocytes found in soft tissues.15

Epidemiology of omental cancer

As omental tumours are rare, there is a lack of information on their worldwide incidence . This study has shown the number of cases  of  tumour histology associated with omental cancers in the United States and worldwide: https://emedicine.medscape.com/article/193622-overview?form=fpf#a1 

Symptoms and diagnosis of omentum cancer

The main symptoms that are associated with omental cancer are: 

  • Constipation
  • Unexplained weight loss
  • Abdominal pain
  • nausea/vomiting 

There are several diagnostic tools used to diagnose an individual with omental cancers. This can demonstrated in Table 1 :

Table 1: illustrates the different f diagnostic tools used to identify omental cancers16:

Diagnostic toolFunction
Computed tomography (CT)Can identify the primary site.
Ultrasonography (US)This diagnostic tool is usually the first to identify whether an individual has a mass in the abdomen. This tool is able to distinguish between cystic and solid tumours. However, a disadvantage of this tool is that it cannot locate the tumour's primary site.
This type of X-ray examines blood vessels and is used when someone is suspected of having an omental tumour.
Magnetic resonance imaging (MRI) Similar to the US,  MRI  can differentiate between cystic from solid tumours. However, a disadvantage of this tool is that it is expensive and time-consuming.


In conclusion, omentum cancer, although rare, poses significant challenges in the diagnosis and treatment due to the limited knowledge and understanding of the omentum’s role in cancer progression. There are two main types of omental cancers: primary omental cancer, which is sporadic and often asymptomatic, in contrast with metastatic omental cancer, which can spread to different sites in the body.  The omentum plays a significant role in fat storage and immune regulation. Further research is required to delve deeper into the omental’s role and understand the mechanism of omental tumours. 


  1. Di Nicola V. Omentum a powerful biological source in regenerative surgery. Regen Ther [Internet]. 2019 Aug 8 [cited 2023 Nov 24];11:182–91. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6700267/
  2. Meza-Perez S, Randall TD. Immunological functions of the omentum. Trends Immunol [Internet]. 2017 Jul [cited 2023 Nov 24];38(7):526–36. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5812451/
  3. Cooper GM. The development and causes of cancer. In: The Cell: A Molecular Approach 2nd edition [Internet]. Sinauer Associates; 2000 [cited 2023 Nov 24]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK9963/
  4. Metastatic cancer: when cancer spreads - nci [Internet]. 2015 [cited 2023 Nov 24]. Available from: https://www.cancer.gov/types/metastatic-cancer
  5. Bahar SG, Rokkam VR. Omentum tumors. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Nov 24]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK563226/
  6. Ono K, Han J. The p38 signal transduction pathway Activation and function. Cellular Signalling [Internet]. 2000 Jan [cited 2023 Nov 24];12(1):1–13. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0898656899000716
  7. MENG A, ZHANG X, SHI Y. Role of p38 MAPK and STAT3 in lipopolysaccharide-stimulated mouse alveolar macrophages. Exp Ther Med [Internet]. 2014 Dec [cited 2023 Nov 24];8(6):1772–6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4218692/
  8. Gkouveris I, Nikitakis N, Sklavounou A. P38 expression and modulation of stat3 signaling in oral cancer. Pathol Oncol Res. 2020 Jan;26(1):183–92. 
  9. nhs.uk [Internet]. 2017 [cited 2023 Nov 24]. Treatment for ovarian cancer. Available from: https://www.nhs.uk/conditions/ovarian-cancer/treatment/
  10. Mukkamalla SKR, Recio-Boiles A, Babiker HM. Gastric cancer. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Nov 24]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK459142/
  11. Wang K, Mei F, Wu S, Tan Z. Hemangiopericytoma: incidence, treatment, and prognosis analysis based on seer database. Biomed Res Int [Internet]. 2020 Nov 2 [cited 2023 Nov 24];2020:2468320. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655240/
  12. Tublin M, Nelson JB, Borhani AA, Furlan A, Heller MT, Squires J. Hemangiopericytoma. In: Tublin M, Nelson JB, Borhani AA, Furlan A, Heller MT, Squires J, editors. Imaging in Urology [Internet]. Elsevier; 2018 [cited 2023 Nov 24]. p. 34. Available from: https://www.sciencedirect.com/science/article/pii/B9780323548090501029
  13. Leiomyosarcoma - nci [Internet]. 2020 [cited 2023 Nov 24]. Available from: https://www.cancer.gov/pediatric-adult-rare-tumor/rare-tumors/rare-soft-tissue-tumors/leiomyosarcoma
  14. Davis DD, Shah SJ, Kane SM. Fibrosarcoma. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Nov 24]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK560759/
  15. Zafar R, Wheeler Y. Liposarcoma. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Nov 24]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK538265/
  16. Solid omental tumors: practice essentials, anatomy, pathophysiology. 2023 Aug 23 [cited 2023 Nov 24]; Available from: https://emedicine.medscape.com/article/193622-overview?form=fpf#a1

Get health & wellness advice into your inbox

Your privacy is important to us. Any information you provide to us via this website may be placed by us on servers. If you do not agree to these placements, please do not provide the information.

Best Milk Alternative
[optin-monster-inline slug="yw0fgpzdy6fjeb0bbekx"]
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Maysaah Seif Suleiman

Bachelors of Science Microbiology, BSc Microbiology, University of Reading

I am a recent Microbiology graduate. I have had the opportunity to contribute to two research projects during my time as an undergraduate; in vitro lung models to assess antimicrobial drug activities and discover a potential diagnostic tool for Mycobacterium bovis.

my.klarity.health presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818