A Rare Case of Diffuse Midline Glioma of Spinal Cord and Literature Review

In the updated World Health Organization classification (WHO, 2016), diffuse midline glioma with histone H3K27M mutation (DMG, H3K27M mutant) is a newly characterized entity that corresponds to a Grade IV diagnosis regardless of tissue histological findings. Less than 100 adult cases of spinal cord DMG, H3K27M mutant have been documented in the literature. In this report, a 42-year-old female was evaluated for weakness of the left lower limb and numbness of the right lower limb, which gradually aggravated to develop difficulty in walking. Magnetic resonance imaging (MRI) showed a fusiform expansile intramedullary lesion of about 5 cm in length involving the conus from the D11 to L1 vertebra. The patient underwent D11–L1 laminectomy and excision of the intramedullary tumor. Histopathology report came as DMG, H3K27M mutant, central nervous system WHO Grade 4. Postoperative MRI showed a residual fusiform expansile lesion of the distal spinal cord and conus medullaris. The patient received adjuvant concurrent chemoradiotherapy followed by received adjuvant tablet temozolomide 150 mg/m 2 , 5-day course every 28 days up to 9 months. One year after radiotherapy, she developed progression of symptoms. As the patient has improved symptomatically initially, this treatment approach can be tried in the case of spinal cord DMG which is difficult to excise completely and has a high chance of recurrence.