Sclerosing mesenteritis

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Sclerosing mesenteritis is an uncommon idiopathic autoimmune condition characterized by inflammation, fat necrosis, and fibrosis of the bowel mesentery. Many patients are asymptomatic; in symptomatic patients, abdominal pain is most common. The diagnosis is increasingly made incidentally via CT imaging, which characteristically shows intestine displaced by a hazy mesenteric fat mass, also known as “misty mesentery.” A presumptive diagnosis is often possible; biopsy is indicated if there are features concerning for malignancy or IgG4-related disease. Treatment of symptoms typically involves immunomodulatory drugs (e.g., tamoxifen, glucocorticoids). Surgery is reserved for patients with bowel obstruction and is not curative. Most patients show no disease progression after 2 years of follow-up.

• Mean age of patients: 55 years
• ♂ > ♀
• Most common in White individuals

Epidemiological data refers to the US, unless otherwise specified.

• The exact cause is not fully understood.
• Generally considered an idiopathic autoimmune disease
• May be associated with: ^[2]
  • IgG4-related disease
  • Metabolic syndrome and obesity
  • Coronary artery disease
  • Urolithiasis
  • Immune checkpoint inhibitors

Patients are often asymptomatic.

Common features ^[2]

• Abdominal pain (most common)
• Bloating
• Diarrhea
• Constipation
• Nausea and vomiting
• Weight loss

Features of severe disease ^[2]

• Bowel obstruction or ischemia
• Mesenteric venous thrombosis
• Sepsis
• Protein-losing enteropathy
• Renal failure
• Ascites

General principles ^[2]

• Sclerosing mesenteritis is most often an incidental finding on CT.
• Rule out alternative diagnoses.
• A presumptive diagnosis can often be made based on characteristic imaging findings.
• Biopsy is not typically required if imaging findings are characteristic and there are no B symptoms.
• Laboratory studies may show nonspecific findings.

Abdominal CT ^[2]

• ≥ 3 of the following findings suggest sclerosing mesenteritis:
  • Intestine displaced by a hazy fat mass in the mesentery (misty mesentery)
  • Nonenhancing perimesenteric fat with higher attenuation than adjacent mesentery
  • Mesenteric lymph nodes < 1 cm
  • Hypoattenuated halo around the central vessels
  • Thin, surrounding fibrotic pseudocapsule
• Calcifications and retractions of the bowel may suggest severe disease and/or malignancy.
• Findings in patients with IgG4-related disease may be atypical (e.g., multiple large lymph nodes, apparent local invasion of organs).

Laboratory studies ^[2]

• ESR and CRP: may be elevated
• Serum IgG4: elevated in ∼ 50% of patients with IgG4-related sclerosing mesenteritis

Biopsy ^[2]

Indications for biopsy include:

• CT findings with signs of malignant lymphadenopathy, e.g.:
  • Lymphadenopathy with lymph nodes > 1 cm
  • Concerning appearance of lymph nodes (e.g., necrosis, calcification)
• Suspected IgG4-related disease (to confirm the diagnosis and exclude malignancy)

• Non-Hodgkin lymphoma
• Peritoneal carcinomatosis
• Carcinoid tumor
• Desmoid tumor
• Encapsulating peritoneal sclerosis
• Retroperitoneal fibrosis
• Pseudomyxoma peritonei

The differential diagnoses listed here are not exhaustive.

General principles ^[2]

• Patients should be managed by specialists (e.g., gastroenterologists).
• Start medical therapy for symptomatic patients.
• Offer symptomatic treatment (e.g., management of constipation).
• Provide expectant management for asymptomatic patients; consider annual CT or MRI for 2 years to monitor for progression.
• Surgery may be indicated for patients with bowel obstruction, but it is not curative.

Pharmacological treatment ^[2]

• Preferred agents include:
  • Tamoxifen (with or without prednisone): most commonly used
  • Colchicine with prednisone
  • Azathioprine with prednisone
  • Prednisone monotherapy for short-term use
• Alternative agents (e.g., rituximab, cyclophosphamide) may be considered in severe, refractory disease.

• Bowel obstruction
• Chronic mesenteric ischemia

We list the most important complications. The selection is not exhaustive.

Except in the most severe cases, the majority of patients have stable disease without radiological progression after 2 years, regardless of whether they receive any treatment. ^[2]