Mesenteric Panniculitis

• The patient presented with abdominal pain. History of receiving treatment of Helicobacter pylori but no relief of symptoms.

Post-contrast CT [axial and coronal cuts]:

• A rather well defined large mesenteric mass-like lesion [red arrows] eliciting misty fat attenuation was noted. It is seen displacing the surrounding bowel loops but not displacing the surrounding mesenteric vascular structures.
• “Tumoral pseudocapsule sign” was evident [green arrows]: it is a peripheral curvilinear band of soft-tissue attenuation that limits the heterogeneous mesenteric mass from surrounding normal mesentery.

• Pay good attention to “mesentery” during reviewing CT abdomen.
• Adjust the window width and length so not to miss fat-like lesions.
• Tumoral pseudocapsule sign sensitivity is 50%.
• The thickness of tumoral pseudocapsule is typically not greater than 3 mm.
• When a misty mesentery is observed on CT, it is important to exclude alternative causes of a regional increase in mesenteric fat density such as oedema, haemorrhage, lymphedema, inflammation, and neoplasia before suggesting a diagnosis of MP.