A case of diffuse midline glioma with histone H3-K27M mutation mimicking long segmental myelitis

Abstract Diffuse midline glioma with H3-K27M mutation is a new tumor entity from 2016 which is highly aggressive and classified as a WHO Grade IV tumor regardless of histopathologic features. We report a case of a 40-year-old male with diffuse midline glioma with pathology confirmation of histone H3-K27M mutation presenting predominately with subacute lower motor neuron syndrome mimicking long segmental myelitis. Our case will remind physicians that diffuse midline gliomas with H3-K27M mutation should be considered for differential diagnosis when there is long segmental spinal cord lesion. Careful evaluation should be done when there is atypical clinical manifestation.