Brainstem Gliomas: An Overview

Abstract

Brainstem gliomas are a heterogeneous group of tumors that affect all ages, although they are predominant in children. There are several grading systems but they are often divided in four subgroups: tectal, diffuse pontine, cervicomedullary and dorsal exophytic. While diffuse pontine gliomas usually are high-grade tumors, the other three subtypes are low- grade lesions (pilocytic astrocytoma or grade II gliomas). The clinical presentation is diverse, but involvement of cranial nerves and long tracts are frequently present. Imaging is crucial for diagnosis and surgical planning and, in the case of diffuse pontine gliomas, MRI has replaced biopsy as gold standard. Treatment includes general measures (control of pain, seizures, physical and speech therapy) that are best addressed by a multidisciplinary team and surgical resection or palliation depending on the extension, grade and location. Since hydrocephalus is common, ventricular derivation followed by observation is the most frequent approach for tectal gliomas. Surgery and/or radiation therapy are reserved for clinical or radiological progression. Diffuse pontine gliomas are inoperable and radiation therapy is the mainstay of treatment leading to transient control of the symptoms. Most cervicomedullary and dorsally exophytic tumors are treated with partial or complete resection when feasible, followed by radiation therapy at time of recurrence or progression. Prognosis is dismal for pontine gliomas, and most patients do not survive 2 years from diagnosis. Outcome is better for tectal, cervicomedullary and dorsally exophytic tumors and many patients achieve a long-term survival, although neurological sequelae are common.