Figure 12c. Tibial nerve neurofibroma in a 30-year-old man. (a) Axial CT scan shows a low-attenuation well-defined mass (arrow) with a center of slightly increased attenuation (white arrowheads) and incomplete fat rim (black arrowheads) (target sign). (b, c) Sagittal T1-weighted (500/17) (b) and axial T2-weighted (2,000/80) (c) MR images reveal entering nerve (open arrow in b), partial fat rim (split-fat sign), and capsule (solid arrow in b) and high-signal-intensity peripheral rim (target sign) (arrowheads in c). (d) Photograph of the axially sectioned gross specimen from debulking surgery shows the capsule (white arrows), peripheral myxoid region (black arrows), and central more solid tissue (*).