There is no generally applied staging system for childhood brain stem gliomas.[1,2,3] It is uncommon for these tumors to have spread outside the brain stem itself at the time of initial diagnosis. Spread of malignant brain stem tumors is usually contiguous; metastasis via the subarachnoid space has been reported in up to 30% of cases diagnosed antemortem.[4] Such dissemination may occur prior to local relapse but usually occurs simultaneously with or after local disease relapse.

The less common tumors of the midbrain, especially in the tectal plate region, have been viewed separately from those of the brain stem because they are more likely to be low grade and have a greater likelihood of long-term survival (approximately 80% 5-year progression-free survival vs. less than 20% for tumors of the pons and medulla).[1,2,3,5,6,7,8,9] Similarly, dorsally exophytic and cervicomedullary tumors are generally low grade and have a relatively favorable prognosis.

References:

1. Cohen ME, Duffner PK, Heffner RR, et al.: Prognostic factors in brainstem gliomas. Neurology 36 (5): 602-5, 1986.
2. Albright AL, Guthkelch AN, Packer RJ, et al.: Prognostic factors in pediatric brain-stem gliomas. J Neurosurg 65 (6): 751-5, 1986.
3. Freeman CR, Farmer JP: Pediatric brain stem gliomas: a review. Int J Radiat Oncol Biol Phys 40 (2): 265-71, 1998.
4. Packer RJ, Allen J, Nielsen S, et al.: Brainstem glioma: clinical manifestations of meningeal gliomatosis. Ann Neurol 14 (2): 177-82, 1983.
5. Halperin EC, Wehn SM, Scott JW, et al.: Selection of a management strategy for pediatric brainstem tumors. Med Pediatr Oncol 17 (2): 117-26, 1989.
6. Epstein F, McCleary EL: Intrinsic brain-stem tumors of childhood: surgical indications. J Neurosurg 64 (1): 11-5, 1986.
7. Edwards MS, Wara WM, Ciricillo SF, et al.: Focal brain-stem astrocytomas causing symptoms of involvement of the facial nerve nucleus: long-term survival in six pediatric cases. J Neurosurg 80 (1): 20-5, 1994.
8. Pollack IF, Pang D, Albright AL: The long-term outcome in children with late-onset aqueductal stenosis resulting from benign intrinsic tectal tumors. J Neurosurg 80 (4): 681-8, 1994.
9. Mandell LR, Kadota R, Freeman C, et al.: There is no role for hyperfractionated radiotherapy in the management of children with newly diagnosed diffuse intrinsic brainstem tumors: results of a Pediatric Oncology Group phase III trial comparing conventional vs. hyperfractionated radiotherapy. Int J Radiat Oncol Biol Phys 43 (5): 959-64, 1999.