Have you ever heard of Mesenteric panniculitis ? It is a disease of the mesentery and the fat tissue or adipose tissue of the intestines. Mesenteric panniculitis is also known with other names or synonyms like Sclerosing mesenteritis or retractile mesenteritis or mesenteric lipodystrophy.
Now you might ask me what is mesentery ? The mesentery is the layer of peritoneum that attaches the abdominal organs like stomach and intestines to the abdominal wall. It acts as a support for these organs.
In this condition of mesenteric panniculitis, fibrosis and inflammation of mesentery and adipose tissue occur. It mainly affects the mesentery attached to the small intestinal parts like ileum and jejunum, but it can also affect the mesentery attached to the sigmoid colon (called mesosigmoid), mesentery attached to the colon (called mesocolon).
Symptoms of mesenteric panniculitis:
Mesenteric panniculitis mainly affects the mesentery and adipose tissue attached to the intestines or the gastrointestinal system. So, the symptoms of this condition are mainly related to this system and the abdominal region.
Males are more likely to suffer from Sclerosing mesenteritis in comparison to women. Adult males are more prone to develop this condition than small boys. The people suffering from retractile mesenteritis develop severe abdominal pain, but the pain is only intermittent.
As the mesentery is fibrosis, we can also feel the presence of an abdominal mass or structure, which is the second most common sign or symptom of this condition. This condition also causes an alteration in the bowel habits like constipation or diarrhea. It can also lead to significant nausea and vomiting.
There can also be a loss of weight and development of fever in mesenteric panniculitis. People suffering from this disease also complain of back pain and passage of blood in the stools sometimes. They can also suffer from fullness in the abdomen, jaundice or increased bilirubin levels in the blood. Mesenteric panniculitis can mimic acute abdomen in rare cases.
The symptoms of mesenteric panniculitis are mainly caused due to the pressure exerted by the abdominal mass or fibrosis of mesentery and adipose tissue on gut, gut blood vessels, and lymphatic vessels.
But these symptoms are only seen in few people suffering from this disease and the majority of the people suffering from it are asymptomatic. Mesenteric panniculitis is detected accidentally when CT or MRI abdomen is done for other reasons in a majority of the people as per a research study.
Stages of mesenteric panniculitis:
Stage 1: Mesenteric lipodystrophy: It is the replacement of fat tissue or adipose tissue of the mesentery by certain cells called foam cells.
Stage 2: Mesenteric panniculitis: In this stage, there is an accumulation of cells like plasma cells (activated B lymphocytes), PMN cells or polymorphonuclear lymphocytes and giant cells in the fat tissue.
Stage 3: Retractile mesenteritis: In this stage, there is deposition of fibers of collagen in the mesenteric fat which leads to fibrosis. Also, there is inflammation of the mesentery and adipose tissue region. This fibrosis leads to the formation of scar tissue which obstructs the abdominal organs like intestines and causes the symptoms of mesenteric panniculitis.
Causes of mesenteric panniculitis:
The exact causes and the mechanism by which mesenteric panniculitis occurs are not clearly known. But some studies have reported that previous history of damage to the abdominal region either due to trauma or due to some sort of abdominal surgery seems to play a vital role in the causation of mesenteric panniculitis.
Some other diseases like vasculitis or inflammation of the blood vessels, mesenteric thrombosis or the thrombosis of the mesenteric blood vessels, injuries caused by various chemicals, medications, and excess heat also seem to affect the development of mesenteric panniculitis.
Some types of infections, hypersensitivity reactions and lack of adequate nutritional support or deficiency of vitamins also lead to mesenteric panniculitis as per preliminary reports.
Diseases of pancreas like pancreatitis, disorders of gallbladder like gallstones or cholelithiasis, diseases affecting liver like cirrhosis, diseases of heart like coronary artery disease are also implicated in causing mesenteric panniculitis.
Also, many different cancers can lead to the development of sclerosing mesenteritis. They are cancers of organs like lungs, skin, colon, kidneys, stomach and also cancer of blood cells like CLL or chronic lymphocytic leukemia and Hodgkin’s disease.
Diagnosis of Mesenteric panniculitis:
The majority of the blood tests in this condition are normal. In rare cases, there can be an elevation of neutrophils called neutrophilia, elevated ESR and deficiency of hemoglobin or anemia.
The most useful test for the diagnosis of mesenteric panniculitis is CT scan abdomen. The CT of people suffering from mesenteric panniculitis shows normal small bowel loops. The superior mesenteric blood vessels appear normal but are surrounded by the disease mass.
The CT of mesenteric panniculitis shows a solitary mass in the adipose tissue of the mesentery. This mass has higher attenuation in comparison to the surrounding adipose tissue in the mesentery.
We can see “fat ring sign” on the CT scan. This sign shows that the fat around the mesenteric blood vessels is spared or is normal. This helps in differentiating this panniculitis from some other disorders like lymphoma.
Sometimes the central part of the abdominal mass in the mesentery can develop necrosis. Furthermore, calcification can also develop within this central part with necrosis. In some cases, any mass might not be found and we can only see increased attenuation of the mesentery. This is called “misty mesentery”.
Although, there are many changes of mesenteric panniculitis that appear on the CT, we need to perform a biopsy to diagnose the disorder accurately. This is because there are many conditions that mimic it on CT. Surgical excision biopsy seems to diagnose mesenteric panniculitis very well in comparison to percutaneous biopsy. But, any of them can be done for a definitive diagnosis. Open surgical biopsy is rarely done and needed.
Differential diagnosis of mesenteric panniculitis:
This condition needs to differentiate from the desmoid tumor, inflammatory pseudotumor, carcinomatosis, lymphoma, mesenteric edema, mesenteric mesothelioma, etc. They mimic mesenteric panniculitis on the CT. So, a biopsy is needed to differentiate these disorders based on the histological findings.
Treatment of mesenteric panniculitis:
There is no perfect treatment regimen that is prescribed to treat mesenteric panniculitis. But, there are many drugs that are being used to treat this condition based on the severity of the symptoms. Most often the treatment of mesenteric panniculitis is only supportive.
Some of the most common drugs used to treat it are steroids or corticosteroids like prednisolone, drugs like colchicines, cyclophosphamide, azathioprine, infliximab, pentoxifylline etc. Some antibiotics are also being tried to treat this disorder. Low dose naltrexone (LDN) seems to be a promising new therapy for this condition. Hormonal therapies like tamoxifen are used to treat fibrosis.
Radiotherapy is not very useful to treat mesenteric panniculitis. Surgery is also not preferred for the treatment as sometimes it worsens the disorder. Surgery is only done if symptoms of bowel obstruction develop in these people.
Prognosis of mesenteric panniculitis:
In some people, lymphoma can develop over the region affected by mesenteric panniculitis. In the majority of the cases, this condition is benign and self-limiting. It resolves itself over a period of time. But, in some patients, it can worsen and can even lead to death.