Diffuse intrinsic pontine glioma (DIPG), now reclassified as diffuse midline glioma (DMG), is the most common cause of mortality from paediatric central nervous system (CNS) tumours. Diagnosis is made based on characteristic clinical presentation and neuro-imaging findings. Prognosis is poor, with minimal therapeutic options, reflected in a median survival of under 12 months. We present a patient with Pendred syndrome, diagnosed with DMG at 2-years of age with characteristic presentation and neuro-imaging findings, who remains asymptomatic and well at nearly 4-years post diagnosis despite progression of the primary lesion on serial imaging.

CNS high-grade neuroepithelial tumor with MN1 alteration (CNS HGNET-MN1) is a rare entity recently described. Thirteen CNS HGNET-MN1 patients were identified using genome wide methylation arrays/RT-PCR across 7 institutions and were correlated with treatment and outcome. All patients had surgery (GTR:9/STR:4) as initial management followed by radiotherapy (focal:5/craniospinal:2/CyberKnife:1) and systemic chemotherapy in 3 patients. Seven patients relapsed; 5 local and 2 metastatic despite complete resection and radiotherapy. Three patients died due to their tumor relapse after 24 months despite upfront radiotherapy. Treatment of CNS HGNET-MN1 remains a major challenge with multiple failures, despite aggressive surgical resections and upfront radiotherapy.