Magnetic resonance imaging of soft-tissue tumors of the extremities: A practical approach

Figure 6 Neurofibroma of the left ulnar nerve (split-fat sign) in a 58-year-old man. A: Coronal T1-weighted image of the left forearm shows a spindle-shaped mass with isointensity relative to adjacent muscle. Note the presence of the split-fat sign (arrows). Because the neurovascular bundle is normally surrounded by fat, masses arising at this site maintain a rim of fat about them as they slowly enlarge; B: Coronal T1-weighted fat-saturated gadolinium-enhanced image shows heterogeneous enhancement of the mass (arrowhead). Recognition of the spindle shape of the tumor and contiguity of the tumor and adjacent nerve may suggest the diagnosis[6].