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[Xanthoastrocytoma inf young subjects. Review of the literature apropos of 2 cases with discordant courses].

Two cases of pleomorphic xanthoastrocytoma (P X A) of young subjects (Kepes et al., 1979) are reported. Case 1 arose in 15-year-old boy admitted to the hospital with the complaint of severe headaches associated with nausea and vomiting of 1 month's duration. Computed tomographic scans showed a large well-defined low density area in the left temporo-parietal region of which an anterior portion was enhanced by contrast medium. Craniotomy revealed a large superficial and cystic tumor with a mural nodule. Histological and immunohistochemical features were those of a P X A confirmed by an electron microscopic study. No radiotherapy was given. The patient made a complete recovery, and 32 months later was asymptomatic. Case 2, a 17-year-old boy was admitted to the hospital in 1977. He presented with seizures that started 18 months prior to surgery. Carotid and humeral angiograms and air studies indicated the presence of a right, internal temporal mass with herniation. The craniotomy revealed a firm superficial tumor with an infratentorial, extraparenchymal extension. The histological diagnosis was giant cell glioblastoma or gliosarcoma. The patient received post-operative radiation of 5.500 rads and chemotherapy (CCNU and VM 26). He died on the 7th post-operative month. In this 2nd case, the diagnosis of P X A was made retrospectively based upon histological and immunohistochemical observations similar to case 1. We are aware of 24 P X A in the literature. In their clinical and histological features these neoplasms resemble closely each other. P X A are superficial, supratentorial astrocytomas occurring in youngs subjects (ages 3 to 32). Their typical microscopic structure include a marked cellular pleomorphism with bizarre giant cells, some mitotic figures and no necrosis. Many cells contain lipid and hyalin droplets in their cytoplasm. Characteristically, the tumoral stroma contain a very rich reticulin fiber network. Immunoperoxidase technique reveal glial fibrillary acidic protein in the tumor cells. Electron microscopic studies demonstrate abundant intracytoplasmic glial filaments. Individual cells or group of cells are surrounded by a prominent basal lamina. Some hemidesmosomes or primitive attachments are seen at the margins of the tumor cells. The biological behaviour of PXA with or without radiotherapy is relatively favorable. Long survival times (up to 25 years) are reported but in 5 cases, P X A follow a less favorable course with malignant transformation and death. Morphologic and immunohistochemical studies support the subpial astrocytic origin of P X A.