Aim: To briefly discuss the imaging features of different types of intra-abdominal fat necrosis.
Background: Trauma and ischemic insult may result in intra-abdominal fat necrosis. Fat necrosis may present with acute abdomen, clinically simulating with other etiologies, such as acute diverticulitis and acute appendicitis.
Main body: Imaging plays a crucial role in making the exact diagnosis and differentiating it from other pathologies that may require surgical intervention. Computed tomography (CT) is the most commonly used imaging modality. A small fat attenuation lesion with a hyperattenuating rim in contact with the ventral surface of the sigmoid colon indicates epiploic appendagitis while a larger fat-attenuation lesion on the right side of the abdomen in between the colon and anterior abdominal wall indicates omental infarction. Fat stranding at the root of the mesentery with fat ring sign represents inflammatory mesenteric panniculitis while retractile or sclerosing mesenteritis appears as a fibrotic spiculated mass with or without calcification, mimicking mesenteric carcinoid. In patients with acute pancreatitis, the amount of inflamed fat correlates with clinical severity and outcome.
Conclusions: Familiarity with the imaging features of different types of intraabdominal fat necrosis helps in establishing an accurate diagnosis, thus avoiding unnecessary intervention.
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