Twelve cases of a distinctive form of supratentorial astrocytoma occurring in young subjects (ages 7 to 25) are reported. The tumors were superficial and involved the leptomeninges extensively. The tumor cells display marked pleomorphism, including bizarre giant cells and a number of mitotic figures, but no necrosis. Many contain large amounts of lipid in their cytoplasm and are surrounded by reticulin fibers, thus simulating a mesenchymal tumor. For these reasons, some examples of this tumor have been previously interpreted to represent meningocerebral fibrous xanthomas. Immunoperoxidase technique performed in nine of the twelve cases has, however, established the presence of glial fibrillary acidic protein in the tumor cells, which are therefore considered to be astrocytic. By electron microscopy many tumor cells are surrounded by basal laminae, accounting for the abundant reticulin network demonstrable in silver preparations. Since subpial astrocytes are known to be partly covered by a basal lamina, it is likely that they are the cells of origin for this neoplasm. In contrast to its pleomorphic cytology, the biological behavior of this tumor appears to be relatively favorable, and long survival times (up to 25 years) have been recorded in some cases. (These tumors are distinct from intracranial fibrous xanthomas of mesenchymal derivation. Cells of the latter are negative on GFAP stain.)

Astroblastomas are rare, usually circumscribed, supratentorial tumors of young subjects and are characterized by a perivascular arrangement of the tumor cells. Their clinical behavior is unpredictable and their prognosis has been regarded as intermediate between that of astrocytomas and glioblastomas. A personal series of 23 astroblastomas was reviewed, adequate postoperative follow-up being available in 13 patients. Two distinct histological types were encountered: low-grade and high-grade. The low-grade type comprised tumors with better differentiated and more benign-appearing microscopical features. Five of the 8 patients with tumors of this type who were available for follow-up have survived from 3 to 20 years after treatment; in I patient the tumor converted into a fatal glioblastoma after 4½12; years. The high-grade type consisted of tumors with more anaplastic features. Three of the 4 patients with tumors of this type available for follow-up died after 1½12; to 2½12; years, the astroblastomas in 2 of them having converted into a glioblastoma and a gliosarcoma, respectively. One patient, however, has had an unexpected length of postoperative survival of 11½12; years. The best clinical results were obtained after total or subtotal resection of the tumor, followed by radiotherapy. The role of chemotherapy is still uncertain. This form of glioma illustrates the discrepancies that may sometimes be apparent between histopathological features and length of postoperative survival. The prognosis is also further complicated by the potential of the astroblastoma to convert into a more malignant type of glioma.

Eleven cases of supratentorial neuroepithelial tumor presenting in infancy are reported. The tumors were characterized by their voluminous size, their intense desmoplasia, and the frequent presence of divergent astrocytic and ganglionic differentiation as demonstrated by special neurohistological and immunohisto- and immunocytochemical techniques. All the tumors presented in subjects below the age of 18 months, usually within the first 4 months of life. They most often involved the frontal and parietal regions and were composed predominantly of a dense desmoplastic tissue superficially resembling a moderately cellular fibroma. The fibroblastic elements were admixed with variable numbers of pleomorphic neuroepithelial cells. Divergent astrocytic and neuronal differentiation was demonstrable in nine of the 11 tumors. All showed astrocytic differentiation. The study of one example by electron microscopy, immunocytochemistry, and tissue culture disclosed that the astrocytic tumor cells were partly invested by a pericytoplasmic basal lamina. Successful total or near-total surgical resection has been followed by a favorable postoperative course extending in some cases over many years of tumor-free survival. The name "desmoplastic infantile ganglioglioma" is proposed for this apparently distinct clinicopathological entity, whose massive size is indicative of a pre- or perinatal origin. Its identification can be achieved by careful histological analysis and is of obvious prognostic significance.

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