Presentation
Abdominal pain.
Patient Data
Hazy mass at the root of the mesentery. Pseudocapsule and fat ring sign on the axial images. Diffuse mucosal hyperenhancement of small bowel, likely related to venous congestion, as the SMV is abruptly narrowed as it enters the mass (best seen on coronal images). Small bowel varices are starting to form. Ascites.
Progressive fibrosis of the mesenteric root over 3 years. Retracted soft tissue mass with punctuate calcifications at the root of the mesentery. Occlusion of the SMV and extensive small bowel wall varices (best seen on coronal). Ascites.
Case Discussion
Sclerosing meseneritis is idiopathic, chronic inflammation of the mesentery. The specific cause is unclear but there are associations with surgery, trauma, autoimmune disorders, vasculitis, infection, and malignancy.1 There can be a relation to IgG4 sclerosis disease.
There are subtypes based on the predominant histopathology, which are shown in their full spectrum in this case: Mesenteric panniculitis (inflammation) at presentation, and retractile mesenteritis (fibrosis) in the 3-year follow-up. This progression is not particularly common or necessarily expected, however.
Notice the narrowing of the SMV and formation of mesenteric and particularly impressive small bowel wall varices. Venous congestion likely accounts for the pronounced mucosal enhancement of the small bowel and ascites on both studies.