Morphological features of gliomas in children.

To elucidate the morphological characteristics of glioma in children, we investigated 83 tumors that occurred in patients under the age of 20 years old. Seven of 20 histologically malignant tumors were adult-type anaplastic astrocytoma and glioblastoma. Eleven tumors were composed of small undifferentiated or poorly differentiated cells. The tumors usually had no fibrillary stroma or if present, the stroma was scanty. A few tumors exhibited ependymal differentiation. One tumor showed rhabdoid features. In 63 benign tumors, including 28 pilocytic astrocytomas and 15 ependymomas, there were 6 plemorphic tumors. Four were regarded as pleomorphic xanthoastrocytoma (PXA), and contained a few neurofilament-positive cells. Further-more, an unclassified glioma composed of eosinophilic plump cells coexpressed glial fibrillary acidic protein and neurofilament protein in identical cells. There were 6 tumors associated with desmoplasia including PXA and desmoplastic infantile astrocytoma (DIA). Characteristics of gliomas in children were considered to be the presence of tumors showing insufficient expression of glial phenotype, expression of neurofilament in some types of gliomas, and the presence of a special type of glioma with conspicuous desmoplasia, including PXA and DIA.