What is mesenteric panniculitis and what causes it?

Mesenteric Panniculitis: Definition and Causes

Mesenteric panniculitis is a rare, benign inflammatory condition characterized by chronic inflammation and fibrosis of the adipose tissue, primarily affecting the mesentery of the small intestine. 1, 2

Definition and Pathophysiology

• Mesenteric panniculitis (MP) is a non-neoplastic idiopathic inflammation of the adipose tissue, mainly affecting the small bowel mesentery 2
• It can be considered a single disease with two pathological subgroups: Mesenteric Panniculitis (where inflammation and fat necrosis predominate) and Retractile Mesenteritis (where fibrosis and retraction predominate) 3
• The condition involves chronic inflammation, fat necrosis, and fibrosis of the mesenteric adipose tissue 1

Clinical Presentation

• MP is asymptomatic in up to nearly half of patients, often detected incidentally on cross-sectional imaging 1
• When symptomatic, the most common clinical manifestation is abdominal pain 1, 2
• Other symptoms may include bloating/distention, diarrhea, constipation, vomiting, anorexia, weight loss, fever, malaise, and nausea 1
• In severe cases, it can cause bowel obstruction due to mass effect 2

Diagnostic Features

• Diagnosis is primarily suggested by computed tomography (CT) imaging 4, 2
• Characteristic CT findings include:
  • A well-defined "mass effect" on neighboring structures 3
  • Mesenteric fat tissue of inhomogeneous higher attenuation than adjacent fat 3
  • Small soft tissue nodes within the affected area 3
  • A hypoattenuated fatty "halo sign" (specific but inconstant) 3
  • A hyperattenuating pseudocapsule surrounding the entity (specific but inconstant) 3
• Surgical biopsy may be required for confirmation in equivocal cases 4, 2

Etiology and Risk Factors

• The specific etiology of mesenteric panniculitis remains largely unknown and speculative 4, 2
• Several potential causes and associations have been proposed:
  • Previous abdominal surgery or trauma 1
  • Autoimmune disorders 1
  • Ischemic injury 1
  • Infections 1
  • Malignancies (particularly lymphoma) 1, 3
  • Inflammatory bowel disease may cause thrombosis around the superior mesenteric vein, potentially contributing to mesenteric inflammation 5

Treatment Approaches

• Treatment should be guided by symptom severity and presence of complications 1
• Medical management options include:
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) 2
  • Corticosteroids (prednisone) as first-line therapy 1, 6
  • Tamoxifen as first-line therapy 1
  • Azathioprine or colchicine as additional options 6
• Surgical intervention is reserved for:
  • Cases where diagnosis is unclear 2
  • When malignancy is suspected 2
  • Severe presentations with mass effect, bowel obstruction, or ischemic changes 2
  • Recurrent bowel obstruction 1

Prognosis

• The course of MP is generally favorable in most cases 3
• Progression from mesenteric panniculitis to retractile mesenteritis appears to be rare 3
• Most patients respond well to medical management, particularly corticosteroids 6

Differential Diagnosis

• The differential diagnosis is extensive and includes all disorders affecting the mesentery 3
• Common considerations include:
  • Lymphoma 3
  • Liposarcoma 3
  • Peritoneal carcinomatosis 3
  • Carcinoid tumor 3
  • Retroperitoneal fibrosis 3
  • Mesenteric desmoid tumor 3
  • Mesenteric inflammatory pseudotumor 3
  • Mesenteric edema 3

Clinicians should maintain a high index of suspicion for mesenteric panniculitis in patients presenting with nonspecific abdominal symptoms, especially when characteristic CT findings are present. While often benign and self-limiting, proper diagnosis and management are essential to exclude malignancy and address symptomatic cases.