Figure 4a.

MR imaging features of well-differentiated liposarcoma in a 74-year-old woman with worsening back pain. (a) Axial T2-weighted MR image shows a well-defined high-signal-intensity mass (straight arrow) in the left retroperitoneum; the mass has internal septa (curved arrow). (b) Axial contrast material–enhanced T1-weighted fat-suppressed MR image shows that the mass (straight arrow) demonstrates a loss of signal intensity, with signal intensity similar to that of the subcutaneous fat. The thin septa (curved arrow) are enhanced. (c) Sagittal T2-weighted MR image shows longitudinal growth of the mass in the retroperitoneum, with well-defined margins (arrows) between the mass and the retroperitoneal fat superiorly.