Sclerosing Mesenteritis is a rare, chronic inflammatory condition of the mesentery—the fold of tissue that secures the intestines to the abdominal wall while providing essential blood supply, lymphatic drainage, and nervous input. The term “mesenteritis” refers to inflammation of the mesentery, while “sclerosing” refers to scarring and fibrosis that can stiffen and damage this supportive tissue. The condition most commonly affects the small bowel mesentery but can occasionally involve the colon mesentery as well.

Although Sclerosing Mesenteritis is not cancerous, its symptoms and imaging findings can closely resemble abdominal malignancies, which often leads to misdiagnosis or delays in treatment. The disease typically involves a combination of fat necrosis, chronic inflammation, and fibrotic tissue formation. Depending on which component dominates, different names are used: mesenteric panniculitis (inflammation and fat necrosis), retractile mesenteritis (fibrosis and scarring), or sclerosing mesenteritis (a broad term encompassing all patterns). While many patients have mild or even asymptomatic disease, some experience severe complications such as intestinal obstruction or ischemia.

This article will explore the causes, risk factors, symptoms, diagnosis, and treatment of Sclerosing Mesenteritis, along with strategies for prevention and living with this condition.

Sclerosing Mesenteritis is a chronic, non-cancerous disorder characterized by inflammation, fat necrosis, and scarring of the mesenteric fat. It is considered part of a spectrum of mesenteric diseases and may be associated with autoimmune mechanisms or prior abdominal trauma. The condition is usually discovered in middle-aged or older adults, often incidentally during imaging studies for other abdominal problems.

Although rare, Sclerosing Mesenteritis is increasingly recognized due to advances in imaging technology. Because it can mimic tumors, infections, or other inflammatory conditions, it often requires careful evaluation and sometimes biopsy to reach a definitive diagnosis.

The exact cause of Sclerosing Mesenteritis remains uncertain, but evidence suggests it arises from a complex interplay of immune dysregulation, trauma, ischemia, and possibly genetic predisposition. Several potential risk factors have been identified.

Possible causes and contributing factors:

1. Autoimmune reactions: The immune system may mistakenly attack mesenteric fat, causing chronic inflammation. Links with lupus, rheumatoid arthritis, and other autoimmune diseases support this mechanism.
2. Previous abdominal surgery or trauma: Many patients report prior abdominal procedures or injury. Abnormal healing responses may lead to persistent inflammation and scarring.
3. Infections: Bacterial or viral infections of the gut may trigger inflammatory responses in susceptible individuals.
4. Ischemia (reduced blood supply): Vascular disease or thrombosis can reduce blood flow to the mesentery, causing fat necrosis and fibrosis.
5. Malignancies: Associations with cancers such as lymphoma, colon cancer, and melanoma have been observed. In some cases, Sclerosing Mesenteritis may represent a paraneoplastic syndrome.
6. Medications and radiation therapy: Chemotherapy, radiation, and certain medications may damage mesenteric tissue, leading to inflammation and scarring.
7. IgG4-related disease: Some cases occur as part of a systemic immune-mediated condition known as IgG4-related disease, which also affects other organs like the pancreas and salivary glands.

The development of Sclerosing Mesenteritis typically follows an abnormal inflammatory process in the mesenteric fat. This can be initiated by immune dysregulation, physical trauma, infections, or reduced blood flow. Over time, persistent inflammation leads to necrosis of fat cells and fibrosis, causing thickening of the mesenteric tissue.

The course of disease varies widely. Some individuals remain asymptomatic for years, while others develop progressive abdominal pain, bowel dysfunction, or even life-threatening complications. The condition occurs most frequently in men aged 50 to 70 but can affect anyone, regardless of age or sex.

Sclerosing Mesenteritis is considered rare, with reported prevalence rates below 1%. However, incidental findings on CT and MRI scans suggest it may be more common than previously thought. The condition is more frequently diagnosed in men, with peak onset in the sixth and seventh decades of life. Because many cases remain asymptomatic or misdiagnosed, its true incidence is likely underestimated.

Symptoms of Sclerosing Mesenteritis vary considerably depending on the severity and stage of disease. Some individuals are completely asymptomatic, while others present with vague, nonspecific complaints that mimic other gastrointestinal conditions.

Common symptoms include:

• Abdominal pain: The most frequent symptom, often dull, crampy, or intermittent.
• Abdominal mass: Sometimes discovered incidentally on imaging or during physical exam.
• Nausea and vomiting: Especially if the mesentery thickens enough to obstruct the intestines.
• Diarrhea or constipation: Bowel motility may be impaired by inflammation or fibrosis.
• Unintentional weight loss: Related to inflammation, malabsorption, or reduced appetite.
• Low-grade fever and fatigue: Reflecting systemic inflammation.
• Bloating and early satiety: Fullness after small meals due to pressure on intestines.

Severe complications may include:

• Intestinal obstruction: Fibrotic tissue compresses bowel loops.
• Chylous ascites: Accumulation of lymphatic fluid in the abdominal cavity.
• Mesenteric ischemia: Restricted blood supply to the intestines.
• Bowel perforation: A rare but serious emergency.
• Fistula formation: Abnormal connections between bowel segments or other organs.
• Obstructive uropathy: Fibrosis can extend into the retroperitoneum and affect the urinary system.

Diagnosis is often challenging due to nonspecific symptoms and similarities with other conditions, particularly abdominal cancers. A combination of imaging, biopsy, and laboratory work is usually required.

Diagnostic methods:

1. Imaging:
   • Ultrasound: Can show mesenteric changes but lacks sensitivity.
   • CT scan: The gold standard, showing features such as fatty masses, the “fat-ring sign,” pseudocapsule, calcifications, or lymphadenopathy.MRI: Provides superior soft tissue contrast and may be used when CT findings are unclear.
   • PET scan: Helps evaluate disease activity and rule out malignancy.
2. Biopsy: Required to confirm diagnosis and exclude cancer. Histological findings typically include fat necrosis, chronic inflammation, fibrosis, and occasionally IgG4-positive plasma cells.
3. Laboratory tests: While no specific blood marker exists, elevated ESR, CRP, or IgG4 levels may support the diagnosis.

Differential diagnosis for Sclerosing Mesenteritis

Because of overlapping clinical and imaging features, several conditions must be ruled out:

• Lymphoma
• Carcinomatosis
• Mesenteric ischemia
• Inflammatory bowel disease
• Retroperitoneal fibrosis
• Pancreatitis

Treatment varies depending on the severity of symptoms, disease progression, and underlying associations. Many asymptomatic patients are managed conservatively with observation, while symptomatic or progressive cases may require medical therapy or, rarely, surgery.

Treatment approaches:

1. Observation (watchful waiting): Appropriate for patients with incidental findings or mild symptoms, with regular follow-up imaging.
2. Medications:
   • Corticosteroids: Such as prednisone, to reduce inflammation and relieve pain.
   • Immunosuppressive agents: Azathioprine, methotrexate, or cyclophosphamide for patients not responding to steroids.
   • Tamoxifen: An anti-estrogen drug with antifibrotic properties, often combined with corticosteroids.
   • Colchicine: Anti-inflammatory agent sometimes effective in controlling symptoms.
   • Thalidomide: Used rarely in refractory cases due to significant side effects.
3. Supportive therapy: Pain management, anti-nausea medication, antibiotics for infections, and nutritional support.
4. Surgery: Reserved for complications such as bowel obstruction, ischemia, or when malignancy cannot be ruled out by noninvasive means.
5. Treatment of underlying conditions: Managing associated autoimmune disease, malignancy, or IgG4-related disease can help stabilize mesenteric inflammation.

Potential complications include:

• Chronic abdominal pain affecting quality of life
• Intestinal obstruction requiring surgery
• Malabsorption and weight loss
• Secondary infections
• Severe ischemia or bowel perforation

Prognosis is generally favorable, especially in mild or incidental cases. Many patients improve spontaneously or with medical therapy. However, in severe cases, ongoing symptoms or complications may significantly impair quality of life. The outcome largely depends on the severity at diagnosis, presence of associated conditions, and response to treatment.

No specific prevention strategies exist, but general measures include:

• Managing autoimmune disorders proactively
• Monitoring patients with prior abdominal trauma or surgery
• Maintaining a healthy diet and immune function
• Seeking prompt medical evaluation for unexplained abdominal symptoms

Living with Sclerosing Mesenteritis often requires regular medical follow-up and lifestyle adjustments. Patients may benefit from:

• Adhering to treatment and medication plans
• Maintaining good nutrition to prevent malabsorption
• Engaging in gentle physical activity as tolerated
• Using relaxation techniques to manage chronic pain
• Seeking psychological support or patient advocacy groups to cope with uncertainty

Sclerosing Mesenteritis is a rare, complex inflammatory disorder of the mesentery. While many cases remain benign and stable, others may mimic malignancy or cause significant complications. Diagnosis is primarily based on imaging, supported by biopsy when necessary. Treatment ranges from observation to corticosteroids, immunosuppressants, and supportive care, with surgery reserved for emergencies. Although prevention is not possible, early recognition and individualized management help improve outcomes and quality of life. Ongoing research into the immune mechanisms underlying the disease may provide more targeted therapies in the future.

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