Idiopathic sclerosing mesenteritis (ISM) or mesenteric panniculitus is a rare disease of the small intestine, characterized by chronic inflammation and eventual fibrosis of the mesentery. It has also been called mesenteric lipodystrophy, or retractile mesenteritis.
Sclerosing mesenteritis may present with no or nearly no signs or symptoms, but many people have chronic and severe pain in the abdomen as the most common chief complaint. Other people have chronic problems with bowel movements, resulting in diarrhea, bloating, gas, and cramping which can range from severe to mild.
The disorder is identified by histopathology showing fat necrosis, fibrosis and chronic inflammation of the small intestine. Examination of the mesentery may indicate a solitary mass, but diffuse mesentery thickening is common.
It often mimics other abdominal diseases such as pancreatic or disseminated cancer. CT scanning is important for making the initial diagnosis.
Several causes of sclerosing mesenteritis have been suggested, but the principal pathophysiological mechanism is probably autoimmune. Trauma and prior surgical procedures have also been indicated as possibilities. It can be found in IgG4-related disease.
In regards to the diagnosis of idiopathic sclerosing mesenteritis, a CT scan which creates cross-section pictures of the affected individuals body, can help in the assessment of the condition.
In terms of possible treatment for the condition of idiopathic sclerosing mesenteritis, medications such as corticosteroids, tamoxifen and thalidomide have been used.
The epidemiology of Idiopathic sclerosing mesenteritis disease is extremely rare and has only been diagnosed in about an estimated 300 patients worldwide to date (as of 2014), it is probably under diagnosed. It can occur in children.
The Mayo Clinic in Rochester reported a large study of 92 patients, with widely ranging severity of their symptoms. The majority were male, with an average age of 65 years. They commonly had abdominal pain (70%), diarrhea (25%) and weight loss (23%). Depending on the stage of the scarring and fibrosis, several different treatments, including surgery for bowel obstruction, or drugs were used to halt the progression of the disease.
In that case series, 56% of patients received only pharmacological therapy, most often receiving tamoxifen with a reducing dose of reducing prednisone, or also had colchicine, azathioprine or thalidomide.
Their findings suggest that sclerosing mesenteritis can be debilitating although relatively benign. Symptomatic patients benefited from medical therapy, usually tamoxifen and prednisone, but further follow-up information would strengthen these results.