Focal brainstem gliomas are a relatively uncommon type of brainstem glioma, which carry a more favourable prognosis compared to the more common diffuse brainstem glioma. The name is a reflection of the imaging findings, which demonstrate a sharply demarcated mass with relatively frequent enhancement on MRI.
The majority are low grade (60%) with most tumours being pilocytic astrocytomas. Gangliogliomas and oligodendrogliomas also occasionally found. Higher grade tumours (40%) are usually fibrillary astrocytoma or GBM.
The histology of focal brainstem gliomas is variable and may be both of low-grade (accounting for the much better prognosis) or high-grade.
Distinguishing between high-grade and low-grade focal brainstem gliomas is clearly important but difficult, and biopsy potentially carries severe morbidity. Diffusion tensor imaging (DTI) and tractography can help by delineating relationship of tracts with respect to the mass. If tract invasion is demonstrated, this suggests a more infiltrating (thus higher grade and poorer prognosis) histology.
- 1. Helton KJ, Phillips NS, Khan RB et-al. Diffusion tensor imaging of tract involvement in children with pontine tumors. AJNR Am J Neuroradiol. 2006;27 (4): 786-93. Pubmed citation
- 2. Koeller Kelly K. and Elisabeth J. Rushing. “From the Archives of the AFIP: Pilocytic Astrocytoma: Radiologic-Pathologic Correlation.” Radiographics 24, no. 6 (November 1, 2004): 1693-1708. doi:10.1148/rg.246045146.
- WHO classification of CNS tumours
- WHO grading of CNS tumours
- VASARI MRI feature set
- diffuse astrocytoma grading
- grade I:
- grade II:
- grade III
- grade IV:
- glioblastoma vs cerebral metastasis
- radiation-induced gliomas
- gliomatosis cerebri (growth pattern)
- specific locations
- treatment response
- Stupp protocol
- glioma treatment response assessment in clinical trials
- multicentric glioblastoma
- multifocal glioblastoma
- prognostic genetic markers