Diffuse Midline Gliomas Harboring the H3 K27M-Mutation in the Bilateral Thalamus and Midbrain: A Case Report and a Review of the Literature

The diffuse midline glioma H3 K27M-mutant was only added recently to the World Health Organization (WHO) Classification of Tumours of the Central Nervous System. While similar tumors are found in the midline, this particular mutation represents the majority of diffuse gliomas in the brainstem. Classified by WHO as grade IV tumors, these are aggressive and bear a poor prognosis for the patient. This report describes a case involving a 37-year-old woman with a histologically confirmed diffuse midline glioma H3 K27M-mutant in the bilateral thalamus and midbrain. The following discussion describes typical characteristics observed with computed tomography and magnetic resonance imaging. Given the rarity of diffuse intrinsic pontine gliomas in adults and the general lack of studies investigating this poorly understood entity, we report critical findings for contribution to the existing scarce literature on the topic.