What is sclerosing mesenteritis and how is it treated in middle-aged to older adults?

Sclerosing Mesenteritis: Definition, Clinical Features, and Management

Definition and Epidemiology

Sclerosing mesenteritis is a rare, benign chronic inflammatory condition affecting the adipose tissue of the small bowel mesentery, characterized by variable degrees of fat necrosis, inflammation, and fibrosis. 1, 2 The disease has a reported prevalence of less than 1%, predominantly affects males (70% of cases), and typically presents in middle-aged to older adults with a median age of 65 years. 3, 2

Clinical Presentation

The clinical presentation varies dramatically from completely asymptomatic to acute abdomen:

• Abdominal pain is the most common presenting symptom, occurring in 70% of patients 3
• Diarrhea occurs in 25% of cases 3
• Weight loss is present in 23% of patients 3
• Some patients present with signs of bowel obstruction or an abdominal mass 1, 4
• The disease can be discovered incidentally on imaging performed for other reasons 2

A critical pitfall is that the nonspecific presentation often delays diagnosis, as symptoms can mimic more common conditions including inflammatory bowel disease, ischemic colitis, malignancy, or diverticular disease. 5, 1

Diagnostic Approach

Imaging

• Computed tomography (CT) is the primary diagnostic modality and typically suggests the diagnosis 1, 2
• CT findings include a "fat ring sign" or "halo sign" representing preserved fat around mesenteric vessels, soft tissue masses in the mesentery, and increased attenuation of mesenteric fat 2
• MRI can be used as an alternative imaging modality, particularly when CT findings are equivocal 4

Histologic Confirmation

• Definitive diagnosis requires histologic evaluation, typically obtained through CT-guided biopsy or surgical biopsy 1, 4
• The histology shows chronic inflammation with variable degrees of fat necrosis, fibrosis, and inflammatory infiltrate 1, 2
• CT-guided biopsy may be inconclusive, and surgical biopsy is sometimes necessary for definitive diagnosis 4

Differential Diagnosis Considerations

In middle-aged to older adults presenting with abdominal symptoms and a mesenteric mass, critical conditions to exclude include:

• Colorectal malignancy (incidence increases dramatically with age) 5
• Ischemic colitis (more common in elderly with cardiovascular disease) 5, 6
• Lymphoma or other retroperitoneal malignancies 4
• Inflammatory bowel disease (15% of new IBD diagnoses occur after age 60) 5

Etiology and Associated Conditions

The etiology remains unknown, but several potential triggers have been identified:

• Previous abdominal surgery or trauma 1, 7, 2
• Autoimmune disorders 4, 2
• Ischemic events 4
• Malignancy (the disease has been associated with concurrent malignancies) 2

Treatment Approach

Treatment is largely empirical due to the rarity of the disease, and management decisions should be based on symptom severity and clinical presentation. 1, 2

Asymptomatic or Mild Disease

• Watchful waiting is appropriate for asymptomatic patients or those with minimal symptoms 7
• Regular clinical and radiologic follow-up to monitor for progression 7

Symptomatic Disease Requiring Medical Therapy

For symptomatic patients, combination therapy with tamoxifen and prednisone appears most effective, with 60% of patients showing improvement in the largest case series. 3

• Tamoxifen combined with prednisone is the preferred medical regimen based on the best available evidence 3
• Non-tamoxifen-based regimens (including steroids alone, antibiotics, or other immunosuppressants like azathioprine) showed only 8% response rates 3, 4
• Medical therapy alone resulted in improvement in 38% of patients 3

Surgical Management

• Surgery is generally limited to obtaining tissue for diagnosis and managing complications such as bowel obstruction 1, 7, 2
• Surgical resection alone resulted in improvement in only 10% of patients 3
• Surgery followed by medical therapy improved outcomes to 20% response rate 3
• The surgical approach is often technically limited due to the inflammatory process and involvement of mesenteric vessels 1

Prognosis and Mortality

Although generally considered benign, sclerosing mesenteritis can have a prolonged debilitating course with potential fatal outcomes. 3

• Deaths occurred in 18 of 92 patients during long-term follow-up 3
• 17% of deaths were directly attributed to complications of sclerosing mesenteritis or its treatment 3
• The disease can cause chronic symptoms requiring long-term management 3, 2

Key Clinical Pitfalls to Avoid

• Do not assume a mesenteric mass is malignant without histologic confirmation, but always exclude malignancy given the age group affected 4, 2
• Do not rely solely on CT-guided biopsy if results are inconclusive; surgical biopsy may be necessary 4
• Do not use surgery as primary treatment for symptomatic disease; medical therapy with tamoxifen and prednisone should be first-line 3
• In elderly patients with abdominal symptoms, maintain a low threshold for excluding other organic pathology including ischemic colitis, malignancy, and inflammatory bowel disease 5, 6