Figure 12a. Chondromyxoid fibroma in a 56-year-old woman. (a) Axial T2-weighted (6,000/112) MR image at the level of the liver (L) shows a mass in the lateral part of the chest wall. The mass has an overall signal intensity higher than that of fat, but multiple septa (arrow) with lower signal intensity also are visible in the tumor. (b) Photomicrograph (original magnification, x100; hematoxylin-eosin stain) reveals fibroblasts intermingled with interstitial myxoid material that accounts for the high signal intensity on T2-weighted MR images.