Fig. 3. Magnetic resonance (MR) image when recurrence and diagnosed dedifferentiated chordoma. (A) Increased extent of heterogeneously enhancing lesion involving from the 2nd to 5th sacrum, sacral canal and presacral space (arrow) and (B) Enhancing mass extended to presacral space (arrow) are observed. Histopathology study of dedifferentiated chordoma in case 2. (C) The area involving high grade sarcomatous component with hypercellularity (H&E stain, ×100). (D) The area involving severely atypical cells with pleomorphic nuclei. Typical chordoma area is not seen (H&E stain, ×400).