Sclerosing mesenteritis is an idiopathic autoimmune disease of the mesenteric fat, increasingly found because of widespread use of CT imaging, and forms a continuum that includes the terms “misty mesentery” and mesenteric panniculitis. Most cases are asymptomatic, do not require treatment, and can be followed. When symptomatic, the abdominal pain on examination should correspond to the sclerosing mesenteritis lesion on imaging and is treated with anti-inflammatory medications tailored to disease severity and clinical response. Biopsy is not required if the sclerosing mesenteritis meets three of the five CT criteria (discussed in the CPU) and lacks features of more aggressive disease or malignancy. There is no surgical cure. Checkpoint inhibitor–associated sclerosing mesenteritis is a unique case that responds readily to steroids and confirms the autoimmune nature of the condition. The most severe sclerosing mesenteritis cases should be considered for referral to tertiary centers with established expertise.
Current treatments are largely corticosteroid-based, often requiring months to achieve a clinical response. Because the etiopathogenesis is unknown and treatment protocols have been empirically derived, future investigation for symptomatic sclerosing mesenteritis should focus on the nature of the inflammatory response, including causative cytokines and other proinflammatory mediators, the goal being targeted therapy with fewer side effects and a more rapid clinical response.