Figure 8a. Chondrosarcoma in a 19-year-old woman. (a) Contrast-enhanced CT scan at the level of the left atrium (A) shows a rib mass with chondroid mineralization (black arrowheads) and invasion of the overlying musculature (white arrowhead). (b) Sagittal T2-weighted (6,000/112) MR image of the lateral chest wall shows a mass arising from the rib (R), with a signal intensity higher than that of intercostal muscle. Areas of low signal intensity (arrowheads) indicate dense mineralization in the tumor.