Fig. 10
Osteoid osteoma versus tibial stress syndrome. A 15-year-old male soccer player with posteromedial tibial pain for 3 months that worsened while training and upon palpation of the upper posteromedial tibia. MRI axial T1 (a), axial (b) and coronal (c) T2 FS showed cortical thickening, periosteal reaction, pes anserinus tendon edema (arrows) and bone marrow edema (asterisk), mimicking a stress syndrome. Further investigation with a CT scan (d, e, f) demonstrated a nidus (dashed arrow), causing this corticoperiosteal reaction (arrowhead) and confirming OO