gms | German Medical Science

Objective: Pilocytic astrocytoma (PA) is the most common glioma in children. Preferred sites include the cerebellum and brain stem. The extent of resection is known to have strong correlations with survival. Depending on the features of the tumour (compact tissue, exophytic growth, displacing of the surrounding tissue), the majority of these tumors are amenable to gross total resection. For brain stem tumors a two staged surgery can be useful to reduce neurological morbidity.

Methods: We present a consecutive series of 18 children (7 M, 11 F) median age of 11,5 (2–18) years harboring a PA in the cerebellum (6 patients) or in the brain stem (12 patients). In 4 patients the gross total removal of the lesion of the brain stem was performed in two phases as previously planned. Image guided surgical navigation system was used in all patients affected by brain stem glioma and in the last part of our series the electrophysiological monitoring (SEPs, MEPs and direct electrical stimulation) was also used.

Results: A gross total removal was performed in almost all cases. In the cerebellar group the morbidity and mortality rate were 0%. In the brain stem group the mortality rate was none and the morbidity was 11% (2/18) All the patients but one (operated in other centre) with preoperative neurological deficits improved after surgery in 4 cases after an initial transient worsening. In one case the tumor undergone malignant transformation after 2 years and the patient died.

Conclusions: PA are focal tumors mostly histologically benign. Surgery alone for these tumors results in a long progression-free survival and good outcome. Neurophysiological mapping and Neuronavigation are recommended for brainstem cases. For brain stem PA a two staged surgery can be considered to minimize neurological morbidity and to achieve a gross total resection.