Fig. 13.

a, b, c, d Benign and malignant neoplastic. ELMSI from an osteoblastoma of the left hemisoma of S1 in a 36-year-old male patient (a–b). STIR coronal image (a) allows to detect an extensive ELMSI (*) involving the left hemisomas of S1 and S2 and the left posterior-lower corner of L5 (arrowhead). In STIR axial image (b) we can see both the ELMSI (*) and the benign nodule of S1 (arrowheads). Marrow alterations from a periosteal osteosarcoma of the proximal diaphysis of the right femur in a 74-year-old woman (c–d). STIR coronal image (c) shows the exophytic development of the tumor (arrow) and the extensive edemigenous reaction of the femoral spongiosa (arrowheads); in d, T1w image, on the axial plane, we can see the tumor (arrows) and the hypointense ELMSI (*) occupying the entire medullary canal