MRI assessment of the bone adjacent to giant cell tumours and its association with local recurrence after intralesional curettage

Pathologically, the paintbrush border sign correlates well with invasion of the bone around GCTB. MMP-9 might play a key role in the formation of penetrating irregular margins. The paintbrush border sign is revealed as a risk factor for local recurrence of GCTB. Sagittal T1-weighted imaging is crucial to diagnose the paintbrush border sign.