Sclerosing mesenteritis: A 46-Year-Old Man Presenting with Abdominal Pain, Nausea, Vomiting, and Weight Loss

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 Sclerosing mesenteritis

Sclerosing Mesenteritis (SM) is a rare, benign, and chronic inflammatory disorder that affects the mesenteric fat of the small intestine. It is characterized by chronic inflammation, fat necrosis, and fibrosis.

1. Cause (Etiology)

The exact cause of sclerosing mesenteritis is unknown. It is considered idiopathic, although several potential associations have been proposed, including:

  • Autoimmune disorders
  • Prior abdominal surgery or trauma
  • Infections
  • Ischemia
  • Malignancy (especially lymphomas and carcinomas)
  • IgG4-related disease (in some cases)

These factors may act as triggers in genetically or immunologically predisposed individuals.

2. Pathophysiology

Sclerosing mesenteritis is a non-neoplastic inflammatory disorder involving the mesenteric fat. It evolves in three overlapping histological stages:

  1. Mesenteric Lipodystrophy: Dominated by fat necrosis with little or no inflammation.
  2. Mesenteric Panniculitis: Inflammation predominates, involving lymphocytes, plasma cells, and macrophages.
  3. Retractile Mesenteritis: Fibrosis becomes the main feature, potentially causing mass effect or bowel obstruction.

These stages are often found together in a single biopsy specimen, reflecting a continuum rather than distinct phases.

3. Epidemiology

  • Prevalence: Rare; exact incidence is unknown due to underdiagnosis and misdiagnosis.
  • Age: Most commonly affects individuals aged 50–70 years.
  • Sex: Male predominance (2.3:1).
  • Geographic distribution: No clear geographic or racial predilection.

4. Clinical Presentation

Clinical manifestations vary and are often nonspecific, leading to delayed diagnosis. Common symptoms include:

  • Abdominal pain (most common)
  • Weight loss
  • Nausea and vomiting
  • Change in bowel habits (constipation or diarrhea)
  • Palpable abdominal mass (in some cases)
  • Fever (less frequent)
  • Ascites (occasionally)

Some cases are asymptomatic and discovered incidentally during imaging for other conditions.

5. Imaging Features

Computed Tomography (CT) is the modality of choice. Classic findings include:


  • "Fat ring sign": Preservation of fat around the mesenteric vessels and nodes.
  • "Misty mesentery": Increased attenuation of mesenteric fat.
  • Soft tissue mass or pseudotumor: Often centrally located in the root of the mesentery.
  • Stranding or fibrosis in the mesenteric fat.
  • Calcifications (occasionally)
  • Enlarged lymph nodes (but usually benign-looking)

MRI and ultrasound can be helpful, but are less specific than CT. PET-CT may be used to exclude malignancy.

6. Treatment

Due to the rarity of the condition, treatment is not standardized. Management is tailored based on severity and symptoms.

  • Observation: For asymptomatic or mild cases.
  • Medical therapy:
    • Corticosteroids (e.g., prednisone) – first-line for inflammation
    • Tamoxifen – anti-fibrotic effect
    • Azathioprine, cyclophosphamide, or methotrexate – in refractory autoimmune-associated cases
    • Colchicine or thalidomide – sometimes used
  • Surgical intervention: Reserved for complications such as bowel obstruction, ischemia, or when malignancy cannot be ruled out.

7. Prognosis

  • Generally benign and indolent.
  • Many cases are self-limited or respond well to medical therapy.
  • Recurrence is rare but possible.
  • Complications can occur due to fibrosis (e.g., bowel obstruction or ischemia).
  • Malignancy association: Some studies suggest a link between SM and underlying malignancy, though this remains controversial. Patients diagnosed with SM should undergo evaluation for concurrent neoplastic processes.
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Case study: A 46-Year-Old Man with Abdominal Pain, Nausea, Vomiting, and Weight Loss 

History and Imaging

  1. A 46-year-old man presented with abdominal pain and nausea.

  2. Contrast-enhanced CT of the abdomen and pelvis was performed.

Quiz:

  1. Where is the most notable finding located?
    (1) Gall bladder
    (2) Liver
    (3) Mesentery
    (4) Spine 

    📝 Explanation:
    Imaging findings, particularly on CT, show abnormalities such as soft-tissue attenuation, small nodules, and a hyperattenuating pseudocapsule located in the mesentery. These are classic features of sclerosing mesenteritis, a rare inflammatory disease primarily affecting the mesenteric fat.

  2. This condition represents a surgical emergency.
    (1) True
    (2) False 

    📝 Explanation:
    Sclerosing mesenteritis is typically not a surgical emergency. It is a chronic, non-infectious inflammatory condition that usually responds to medical management. Surgery is only considered if complications such as bowel obstruction occur, which is uncommon.

  3. Which laboratory value is commonly elevated in patients with this condition?
    (1) CA 19-9
    (2) ESR (Erythrocyte Sedimentation Rate)
    (3) Lactate
    (4) Lipase 

    📝 Explanation:
    Due to its inflammatory nature, sclerosing mesenteritis is frequently associated with elevated inflammatory markers like ESR and CRP.

    • CA 19-9 is a tumor marker, usually elevated in malignancies.

    • Lactate is elevated in tissue hypoxia or ischemia.

    • Lipase is elevated in pancreatic inflammation.
      Thus, ESR is the most commonly elevated value in this context.

  4. This condition is primarily treated with antibiotics.
    (1) True
    (2) False 

    📝 Explanation:
    Antibiotics are not the mainstay of treatment for sclerosing mesenteritis, as it is not an infectious disease. Treatment typically involves:

    • Corticosteroids to reduce inflammation

    • Tamoxifen for its anti-fibrotic effects

    • Immunosuppressive agents in some cases
      Antibiotics may be used if a secondary infection is suspected, but they are not first-line therapy.

Findings and Diagnosis

Key Findings

CT: Ill-defined attenuation was observed in the proximal mesentery, with multiple small nodules along the proximal mesenteric vessels. A mild mass effect on adjacent structures was noted. A hypoattenuating pseudocapsule was visible, and no fluid collection was identified.

Differential Diagnosis

  • Carcinoid tumor

  • Carcinomatosis

  • Desmoid tumor

  • Mesenteric lymphoma

  • Sclerosing mesenteritis (final diagnosis)

Diagnosis:

Sclerosing Mesenteritis

Discussion

Sclerosing Mesenteritis

Pathophysiology

The exact pathophysiology of sclerosing mesenteritis is not fully understood. Histopathologic studies suggest a progression from fat necrosis to chronic inflammation and ultimately fibrosis.
A 2017 systematic review of 192 reported cases found the most commonly associated factors to be:

  • Prior abdominal trauma or surgery (28.6%)

  • Malignancy (8.9%)

  • Autoimmune disease (5.7%)

Epidemiology

Radiologically estimated prevalence based on CT findings is approximately 2.5%.
Most cases occur in individuals aged 50–70 years.
There is a male predominance (ratio of about 2:1).

Clinical Presentation

Patients may be asymptomatic or present with nonspecific symptoms such as:

  • Abdominal pain

  • Weight loss

  • Nausea

  • Vomiting

Up to half of the patients may show no abnormal physical findings.
About one-third may have a palpable abdominal mass, and fewer than one-third may exhibit nonspecific abdominal tenderness.
Inflammatory markers such as ESR and CRP may be elevated.

Imaging Findings

CT:

  • A classic feature is “misty mesentery”, indicating increased density of mesenteric fat.

  • This is not pathognomonic for sclerosing mesenteritis.

  • Small lymph nodes and calcifications may also be seen in the area.

In 2011, Coulier et al. published a list of five CT diagnostic criteria for sclerosing mesenteritis.

Although these criteria have not been histopathologically validated, they have since been widely used by various authors in diagnosing the condition. The five criteria are as follows, with the fourth and fifth signs being less sensitive but more specific:

  • Presence of a well-defined “mass effect” on adjacent structures

  • Involvement of mesenteric fat that shows higher and inhomogeneous attenuation compared to adjacent retroperitoneal or colonic fat

  • Presence of small (<10 mm) soft tissue nodules

  • Fat halo sign: hypoattenuating fat surrounding nodules or mesenteric vessels

  • Presence of a hyperattenuating pseudocapsule surrounding the lesion, even in the absence of ascites or known peritoneal malignancy

⚠️ Due to the broad differential diagnosis that includes malignant processes, many patients eventually undergo biopsy for a definitive diagnosis.

The most common neoplastic differential diagnoses include:

  • Carcinoid tumor

  • Desmoid tumor

  • Lymphoma

Treatment

Treatment depends on the extent of imaging findings and the presence or severity of symptoms. Many patients are asymptomatic or only mildly symptomatic.
If a biopsy confirms sclerosing mesenteritis, some authors recommend observation alone.

The mainstay of medical therapy is corticosteroids. However, other agents such as colchicine, tamoxifen, and 6-mercaptopurine have also been reported.

Surgical treatment is generally reserved for complications such as bowel obstruction.
In a case series of 92 patients, 20 underwent surgery, but only 2 patients responded to surgery alone.

References

  1. Coulier, B. (2011). Mesenteric panniculitis. Part 2: prevalence and natural course: CT study. Journal: Journal of the Belgian Society of Radiology
  2. van Putte-Katier, N. et al. (2014). Sclerosing mesenteritis: clinical characteristics, treatment, and outcome. Journal: PLoS ONE, 9(10): e110883
  3. Emory, T. S., Monihan, J. M., Carr, N. J., & Sobin, L. H. (1997). Sclerosing mesenteritis, mesenteric panniculitis, and mesenteric lipodystrophy: A single entity? Journal: American Journal of Surgical Pathology, 21(4), 392–398
  4. Sabate, J. M. et al. (2009). Sclerosing mesenteritis: Imaging findings in 17 patients and literature review. Journal: European Journal of Radiology, 69(1), 86–93
  5. Kipfer, R. E., Moertel, C. G., & Dahlin, D. C. (1974). Mesenteric lipodystrophy. Journal: Annals of Internal Medicine, 80(5), 582–588

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