Diffuse midline glioma

Case contributed by Anson Chan
Diagnosis certain


3-month history of headaches with blurred vision. Papillodema on examination.

Patient Data

Age: 25 years
Gender: Male

CT head +/- contrast


A non-enhancing isodense lesion is demonstrated in the region of the right thalamus. There is obstructive hydrocephalus of the lateral ventricles.

MR brain with contrast


A homogenous T2/FLAIR hyperintense lesion is demonstrated to the right of the third ventricle. This results in effacement of the third ventricle with associated moderate hydrocephalus and midline shift. Transependymal CSF spread is identified. No contrast enhancement is noted.

Case Discussion

This case demonstrates imaging features of a diffuse midline glioma with associated obstructive hydrocephalus.

The histopathology was confirmed via endoscopic biopsy.


3rd ventricular lesion: Sections show scanty cellular material composed of spindle to oval nuclei. No definite perivascular pseudo rosettes are seen. No definite mitotic activity is seen within the sparse tissue. No definite papillary architecture. Clear cell morphology, gemistocytic astrocytes or giant cells are not seen. There is no evidence of microvascular proliferation or necrosis. The overall features are of a glial lesion representing a glial neoplasm.


  • P53: Probable wild-type pattern of staining.

  • ATRX: Not interpretable.

  • H3 K27M: Probable positive showing variable weak to strong staining in most atypical nuclei.

  • H3 K27me3: Probable negative.

  • IDH1-R132H: Negative.

  • BRAF-V600E: Negative

  • Ki67: Occasional tumor cell nuclei are positive, but the percentage is not able to be given because of the low tumor content.


Features, in the context of the imaging findings, are those of a diffuse midline glioma, K27M-mutant.

Tissue sections were referred for sequencing, unfortunately, there was insufficient tumor tissue for next-generation sequencing. However, pyrosequencing was attempted and identified the H3 K27M variant consistent with the immunohistochemical results.

Final diagnosis

Third ventricle lesion: Diffuse midline glioma, H3 K27-altered; - WHO grade 4.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.