Astrocytic Tumors

In the group of gliomas, pilocytic astrocytoma (grade 1) of the cerebellum is the most common tumor, account ing for 25% of all intracranial tumors in children. When totally resected, the prognosis is excellent, with a 15- to 20-year survival rate. A malignant variant occasionally develops following radiation therapy for a benign astrocytoma.

Desmoplastic infantile astrocytoma and desmoplas-tic infantile ganglioglioma (grade1), large cystic tumors of the cerebral hemispheres with dural attachment, have a generally good prognosis following surgery.

Subependymal giant cell astrocytoma (grade 1), a histologically benign tumor in the wall of the lateral ventricle, occurs in the setting of tuberous sclerosis complex.

Pleomorphic cystic xanthoastrocytoma (grade 2), a less common tumor of the cerebral hemispheres, has a favorable prognosis, but may occasionally recur and may undergo malignant transformation.

Low-grade diffuse astrocytoma (grade 2) of the cerebral hemispheres has a better prognosis and less frequent malignant progression than does the adult counterpart.

Anaplastic astrocytoma (grade 3) and glioblastoma multiforme (grade 4) account for about 7% of pediatric tumors each. Anaplastic astrocytomas that show gains of chromosome 1q lead to a shorter survival.

Ependymoma (grade 2), the second most common childhood glioma, is a relatively benign tumor of the fourth ventricle; it constitutes 6% to 12% of pediatric tumors. The prognosis is influenced by its amenability to total resection.

Choroid plexus papilloma (grade 1), a rare tumor, has a good prognosis when totally resected. Prognosis is better with diploid papilloma than it is with aneu-ploid, which is aggressive. The prognosis for its malignant variant, the choroid plexus carcinoma, is poor. Both tumors have a tendency to disseminate via CSF.

Oligodendroglioma accounts for only 1% to 2% of pediatric tumors. Unlike the adult counterpart, no particular genetic alteration is associated with prognosis.

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