Figure 1: (a) MRI showed osseo-cartilaginous mass within the ankle joint space. (b) Grossly, two white bony hard nodular tissue pieces measuring 1.5 × 1 × 0.7 cm and 1.8 × 1.5 × 0.8 cm. (c and d) Microscopy showed circumscribed nodules of central cartilaginous areas with endochondral ossification and fibrotic synovial membrane at the periphery (HE, ×100 and × 400)