Question: A 69-year-old male presented with a 20-year history of left calf swelling that began following a fall from a tree (Figs. 1, 2 and 3).

Fig. 1
figure 1

(a) AP and (b) lateral radiographs of the left calf

Fig. 2
figure 2

(a) coronal T1W TSE and (b) axial PDW FS TSE MR images of the left calf

Fig. 3
figure 3

(a) Histology (H&E × 10). (b) (H&E × 20)