The H3.3K27M Mutation and its Role in Pediatric Midline Gliomas: Case Report and Review of the Literature

First identified in 2012, the histone 3 mutation H3.3K27M significantly affects the prognosis of children with anaplastic astrocytoma (AA) and other gliomas. Tumors with this mutation tend to be more aggressive and localize along the midline, behaving like diffuse intrinsic pontine gliomas (DIPGs). Surgical options are often limited because of the deep location of these tumors coupled with their invasive and infiltrative nature. Additionally, AA with this histone mutation is more resistant to chemotherapy and radiation treatment. Given this aggressive and resistant behavior, children with thalamic and/or hypothalamic AA with this mutation have a lower than expected life expectancy of roughly 1 year. In this case report of an 11-year-old female with anaplastic astrocytoma and the H3.3K27M variant, the authors describe the diagnostic importance of genetic and/or immunohistochemistry testing to identify this mutation. We review the relevant literature about the H3.3K27M mutation and discuss the implications that the mutation may have on the management of children with these neoplasms.