Extrahepatic Fat-Containing Lesions of the Abdomen and Pelvis: An Organ-Based Approach to Differential Diagnoses

The presence of intralesional fat provides an invaluable tool for narrowing the differential diagnosis for both benign and malignant neoplasms of the abdomen and pelvis. The ability to characterize intralesional fat is further expanded by the ability of magnetic resonance imaging to detect small quantities (intravoxel) of fat. While the presence of intralesional fat can help to provide a relatively narrow set of diagnostic possibilities, depending on the type of fat (macroscopic vs intravoxel) that is present and the organ of origin, radiologists must be aware of uncommon mimickers of pathology, both benign and malignant.