الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
CNS tumours constitute a very important entity of paediatric tumours. There are many classification systems that deal with the different CNS tumours. The recent WHO classifications (1993 & 2000) are widely applicable. This study was done on 82 cases of paediatric CNS tumours which were received during the period from January/96 to January 10 I. The cases were collected at Pathology department, Mansoura Faculty of medicine as paraffin blocks, resectioned and stained by H&E stains and immunohistochemical stains for selected cases (OF AP, NSE and ki67). 19 cases in this study were medulloblastomas (23%). 17 cases were pilocytic astrocytomas (20.7%).6 cases were low grade diffuse fibrillary astrocytomas (7.3%), one case was anaplastic astrocytoma, one case glioblastoma multi forme, one case was subependymal giant cell astrocytoma (SEGA) and one case was desmoplastic cerebral astrocytoma of infancy (DC I), 11 cases were ependymomas (13.4%) and one case was mixed glioma (ependymo-astrocytorna). 9 cases were craniopharyngiomas (11 %). 4 cases were meningiomas (4.9%). Two cases were present for each prirnative neuroectodermal tumours (PNET), choroid plexus papillomas and schwannomas. Two cases were epidermoid cysts and one case was dermoid cyst. There were one lipoma and one cavernous haemangiorna. This showed that the most common paediatric CNS tumours were medulloblastoma occurring mainly between 5-10 years. The second most common tumour was pilocytic astrocytoma occurring mainly between 10-15 years. Ependymoma followed medulloblastoma and pilocytic astrocytoma and its peak of incidence was in earlier age than them (the 1st five years of life). As regard the location of the tumours, more than half of the cases (52.4%) originated in the posterior fossa whereas the cerebral hemispheres were the original sites for about 17.1 % of cases. The suprasellar region came after the posterior fossa and the cerebral hemispheres as 13.4% of cases occupied the suprasellar region. Brain tumours occurring during infancy had some specific features. These tumours gave rise to clinical presentations different from those of older children. These tumours were usually low-grade astrocytomas.