Figure legends:
Figure 1. T2-weighted MRI, Axial sections, sequences at the level of the pons.
  1. Diagnostic MRI shows high T2 signal and enlargement of the pons encasing the basilar artery and left lateral extension towards the cerebellar peduncle and left cerebellar hemisphere consistent with DIPG.
  2. 3 month-follow up MRI after surgical biopsy and radiation therapy shows significant reduction of the pontine tumefaction and cerebellar peduncle extension compatible with partial response.
  3. 15 months after first irradiation, there is new enlargement of the pons with high signal consistent with progressive disease.
  4. MRI after reirradiation. There is a new radiological improvement with reduction of the pons size and less high T2 signal compatible with partial response.17
Figure 2. Sagittal FLAIR + post-gadolinium at relapse (A) and after re-irradiation (B).
Both the primary brainstem lesion and the metastasis (anterior recesses of the III ventricle, in relation with the corpus callosum and mid-line frontal lobes) show volume
reduction and improvement of signal abnormality.