Sclerosing mesenteritis is a chronic inflammatory condition that affects your mesentery, which is part of your peritoneum. It causes fibrosis (scarring) of the tissues. You may have symptoms of abdominal pain and swelling. The inflammation in this condition is idiopathic. It may be a type of autoimmune response.
Sclerosing mesenteritis is a rare disease that affects your mesentery, the tissue that attaches parts of your intestines to the back wall of your abdomen. “Mesenteritis” means inflammation of the mesentery, and “sclerosing” means scarring. Sclerosing mesenteritis causes chronic inflammation of the mesentery. Over time, chronic inflammation causes scarring or “fibrosis” of the tissues, making them harden.
Your mesentery is part of your visceral peritoneum, the tissue that wraps around your abdominal organs and helps hold them in place. It’s composed of a double layer of folded peritoneum with a layer of fatty tissue in between. Inflammation in sclerosing mesenteritis affects the fat layer (adipose tissue). It causes it to thicken and harden, usually in one or several spots, which can look like masses on radiology images.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
It takes consistent inflammation over a long period of time to cause sclerosis. It happens in stages: first, the fat begins to break down, then different types of cells begin to infiltrate the tissue, and finally, scar tissue develops. So, by definition, sclerosing mesenteritis is a chronic condition and a progressive one. But that being said, it doesn’t always continue to progress, and it often goes away on its own.
Most healthcare providers treat them as the same condition. They’re both described as “idiopathic” inflammation of the mesentery, which means that the inflammation appears to occur spontaneously. However, some have suggested that “sclerosing mesenteritis” should be used to describe a more advanced stage of the disease, or a more severe form, when it lasts longer or the symptoms are worse.
“Mesenteric panniculitis” literally means inflammation of the fat tissue of the mesentery. Since the name doesn’t reference sclerosis, some argue that mesenteric panniculitis should be used to describe an earlier stage of inflammation, before scarring takes place. They argue that when sclerosis sets in, it means the disease has progressed a long way and may be more complicated or more difficult to treat.
Sclerosing mesenteritis is rare, affecting only about 0.6% of the population. Only about 200 cases have ever been reported, so we’re still in the early stages of learning about it. It most often affects people after the age of 50. Many people affected have a family history of autoimmune diseases. Research also suggests that as many as 60% of cases may be linked to prior or current cancer, especially lymphoma.
It’s not a cancer in itself, although it’s often associated with cancer. Cancer is one possible cause of chronic inflammation. Infectious diseases are another possible cause. Research suggests that people who’ve experienced inflammation from one of these causes are more likely to develop sclerosing mesenteritis. It’s as if their mesentery “catches” the inflammation and continues to keep it alive.
Scar tissue doesn’t multiply the way that cancer does, but it can appear to “spread,” and it can look like cancer on radiologic studies. Sclerosing mesenteritis is often characterized by a solid, focal “mass” of scar tissue in your mesentery, resembling a tumor. The two conditions can also present with similar symptoms. It can take some time and testing for healthcare providers to definitively tell them apart.
Many people have no symptoms at all and are unaware they have the condition. The most common symptoms people report are abdominal pain and bloating. Severe inflammation may trigger diarrhea or fever. You may be able to feel a palpable mass when you touch your abdomen. In rare cases, a mass may obstruct your small intestine, causing additional symptoms of nausea, vomiting and weight loss.
The exact cause is unknown, but healthcare providers suspect that it’s a type of autoimmune disease. That means the inflammation is an inappropriate or overreactive immune response. Your immune system uses inflammation to fight off invaders and heal wounded tissues. When your immune system activates in this way without any apparent threat, it’s called an autoimmune response.
There are many different types of autoimmune diseases that cause chronic inflammation in different body parts. We don’t know why they occur, but they appear to be partly genetic and possibly triggered by physical stress, such as illness or injury. People who get sclerosing mesenteritis often have a family history of autoimmune disease, and sometimes they have other autoimmune diseases themselves.
Imaging
Your healthcare provider will take radiological images of your mesentery to look for the characteristic signs of sclerosing mesenteritis. They may see the first signs on an abdominal ultrasound, which is quick and easy to do. When they suspect SM, they’ll proceed to a more sensitive imaging test, such as a CT scan (computed tomography scan) or MRI (magnetic resonance imaging). They’ll look for a focal mass with signs of tissue breakdown and fibrosis around it.
If these tests can’t distinguish between sclerosing mesenteritis and cancer, a PET scan may help to confirm the diagnosis. PET stands for positron emission tomography. It’s a type of nuclear medicine imaging that works by injecting a safe, radioactive tracer into your body. A CT scan or MRI can detect the radiation while producing images. Cancer cells absorb more of the radioactive tracer than other cells.
Biopsy
If all else fails, your provider may need to take a tissue sample of your mesentery for biopsy. A pathologist will analyze the tissue sample to make the final diagnosis. Usually, they can take the tissue sample (biopsy) through a needle inserted into your abdomen. Some people may need to have minimally invasive surgery to examine their mesentery and take the sample (laparoscopy).
Many people will never need treatment. Sclerosing mesenteritis tends to be self-limiting and often goes away by itself. It may never cause you symptoms or may cause only mild discomfort that you can manage with over-the-counter (OTC) medications. However, if you do have persistent symptoms, your healthcare provider will offer various prescription medications to treat them. These may include:
For most people, the prognosis (outlook) is good, but it can vary from person to person. Most people have mild to moderate symptoms, if any, but occasionally, it manifests as a more aggressive condition. It can last for a couple of days or as long as 10 years. It often goes away on its own, or with medications, but sometimes it doesn’t. It may take some trial and error to find the treatment that works best for you.
An anti-inflammatory diet can help to reduce chronic inflammation in your body, particularly in your digestive system. It’s not enough to make sclerosing mesenteritis go away, but it could make a difference in your symptoms. An anti-inflammatory diet emphasizes whole foods found in nature over processed foods found in a package. It also emphasizes healthy, unsaturated fats, such as omega-3s.
A note from Cleveland Clinic
Sclerosing mesenteritis is a mysterious condition that can take you by surprise. Some people develop it following an infection, abdominal surgery or cancer. Others develop it for unknown reasons. You may have symptoms, or your healthcare provider may discover it incidentally. It can be unsettling to have a condition that’s still not well understood. Your healthcare provider will work with you one-on-one to solve it.
Last reviewed by a Cleveland Clinic medical professional on 09/12/2023.
Learn more about our editorial process.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy