Glioma
In this chapter we survey the clinical and pathophysiologic principles of gliomas, the primary tumors of the central nervous system. We describe the histologic and clinical features of the main glioma subtypes, including diffuse astrocytic and oligodendroglial gliomas, as well as circumscribed gliomas such as pilocytic astrocytoma and ependymoma. In 2016 the World Health Organization incorporated genetic markers into the diagnostic criteria for gliomas. We discuss the key molecular discoveries that underlie these diagnostic changes, including IDH mutations and 1p/19q codeletion in diffuse gliomas, and the RELA fusion in ependymomas. We provide an overview of the molecular processes and pathways fundamental to gliomagenesis, including disruptions in cell cycle checkpoints, growth factor signaling, telomere maintenance, and epigenetic regulation. Finally, we highlight the physiologic mechanisms of important clinical sequelae of gliomas, including cerebral edema, immune dysregulation, and systemic hypercoagulability.
