A case of adult‐onset diffuse midline glioma diagnosed by histone H3K27M immunostaining after death, which required differentiation from brainstem encephalitis and myelitis

Abstract

H3K27M‐mutant diffuse midline glioma is a malignant glioma that was newly added to the World Health Organization classification in 2016. In diffuse midline glioma, the H3K27M‐mutant sometimes develops sub‐acutely and requires a differential diagnosis from encephalomyelitis. Here, we report a case of adult‐onset diffuse midline glioma that was diagnosed by immunostaining for histone H3K27M after death. The present case required a differential diagnosis of autoimmune cervical myelitis and brainstem encephalitis.