[Atypical teratoid rhabdoid tumor: case report]. / Atipik teratoid rabdoid tümör: olgu sunumu.

Atypical teratoid rhabdoid tumor is a rare highly malignant embryonal tumor of the central nervous system that is often seen in early childhood. It is very important to distinguish it from other brain tumors because it has a very poor prognosis and there are differences in its treatment. A case of atypical teratoid rhabdoid tumor in a six-week-old male baby is presented. The tumor was located at posterior fossa. Histopathologically, the tumor has rhabdoid tumor cells and mesenchymal components beside the undifferentiated small cells. While EMA, vimentin, synaptophysin and smooth muscle actin have been stained with immunohistochemical staining, desmin, chromogranin, CD 99 and CD 56 have not been stained. The patient died four months after surgery despite the chemotherapy given. In conclusion, morphological characteristics can vary to a large extent that it is difficult to recognize atypical teratoid rhabdoid tumor. Immunohistochemical panel and molecular genetic study will help to establish the correct diagnosis.

p53 protein alterations in adult astrocytic tumors and oligodendrogliomas.

BACKGROUND: p53 is a tumor suppressor gene implicated in the genesis of a variety of malignancies including brain tumors. Overexpression of the p53 protein is often used as a surrogate indicator of alterations in the p53 gene. AIMS: In this study, data is presented on p53 protein expression in adult cases (>15 years of age) of astrocytic (n=152) and oligodendroglial (n=28) tumors of all grades. Of the astrocytic tumors, 86% were supratentorial in location while remaining 14% were located infratentorially - 8 in the the cerebellum and 13 in the brainstem. All the oligodendrogliomas were supratentorial. MATERIALS AND METHODS: p53 protein expression was evaluated on formalin-fixed paraffin-embedded sections using streptavidin biotin immunoperoxidase technique after high temperature antigen retrieval. RESULTS: Overall 52% of supratentorial astrocytic tumors showed p53 immunopositivity with no correlation to the histological grade. Thus, 58.8% of diffuse astrocytomas (WHO Grade II), 53.8% of anaplastic astrocytomas (WHO Grade III) and 50% of glioblastomas (WHO Grade IV) were p53 protein positive. In contrast, all the infratentorial tumors were p53 negative except for one brainstem glioblastoma. Similarly, pilocytic astrocytomas were uniformly p53 negative irrespective of the location. Among oligodendroglial tumors, the overall frequency of p53 immunopositivity was lower (only 28%), though a trend of positive correlation with the tumor grade was noted - 25% in Grade II and 31.5% in grade III (anaplastic oligodendroglioma). Interestingly, p53 labeling index (p53 LI) did not correlate with the histopathological grade in both astrocytic and oligodendroglial tumors. CONCLUSIONS: Thus, this study gives an insight into the genetic and hence biological heterogeneity of gliomas, not only between astrocytic tumors vs. oligodendrogliomas but also within astrocytic tumors with regard to their grade and location. With p53 gene therapy trials in progress, this will possibly have future therapeutic implications.

A rosette-forming glioneuronal tumor of the fourth ventricle: infratentorial form of dysembryoplastic neuroepithelial tumor?

Eleven cases of a distinctive tumor of the posterior fossa are described. The patients (age range 12-59 years) presented with headache and/or ataxia. Neuroimaging revealed a relatively discrete, focally enhancing mass(es) primarily involving the aqueduct, fourth ventricle, and cerebellar vermis. Hydrocephalus was present in seven cases, and two lesions were multicentric. In two cases a significant increase in tumor size was documented. Gross total or subtotal resections were achieved in 10 cases. One patient underwent biopsy alone and another received postoperative irradiation. Histologically, two components were identified in all cases. One consisted of neurocytes forming neurocytic and/or perivascular pseudorosettes in a fibrillary, partly microcystic matrix. The second, astrocytic component resembled pilocytic astrocytoma in 10 cases and consisted of fibrillated spindle cells with oval nuclei associated with occasional Rosenthal fibers, granular bodies, glomeruloid capillaries, and microcalcifications. Regionally, this component was more diffuse and patternless, consisting of sheets of round to oval, oligodendrocyte-like cells. Rare ganglion cells were seen in four cases. The rosettes were consistently synaptophysin and MAP-2 immunoreactive, whereas the spindle cells were positive for S-100 protein and glial fibrillary acidic protein. Overall, atypia was minimal; no mitoses were found, and Ki67 labeling indices were low. Ultrastructurally, the neurocytic cells featured processes containing microtubules and occasional dense core granules. Mature synapses were found in one of the four cases studied. Although the histologic features of this unique tumor superficially resemble those of dysembryoplastic neuroepithelial tumor, rosette formation by neuronal cells, the frequent presence of a pilocytic astrocytoma component, and the growing nature of the lesion argue against that diagnosis, as does occasional multifocality.

Study on ganglioside composition in brain tumours supra- and infratentorial.

The composition of gangliosides in primary tumors depends on their histological origin and differentiation grade (biological malignancy). The aim of the present study was the comparison of gangliosides in various types of brain tumours. The studies were performed on specimens from 20 high grade gliomas, 5 low grade gliomas, 8 meningiomas and 9 metastatic tumours. The isolated gangliosides were separated on silica 60 HPTLC plates and their mobilities were compared with glycolipids standards. The following observations were made: 1. high and low grade gliomas had similar ganglioside profiles comprising 7 different species; 2. the profiles of gangliosides isolated from metastatic neoplasms differ considerably from those of gliomas as well as menigiomas.

[Clinicopathologic analysis of ependymoma in childhood].

A review of the clinicopathologic features of 23 ependymomas in children was made, of which 17 were male and 6 female, the male:female ratio being 2.8:1. Their average age was 8.8 years. Seven of the 23 ependymomas were supratentorial, 16 were infratentorial. The mean duration of symptoms prior to operation in the two groups was 5.3 and 3 months respectively. Histologically, the tumor could be classified into three types: papillary (or myxopapillary), epithelial and cellular. According to the degree of differentiation, the tumor could be divided into typical ependymoma and anaplastic ependymoma. Immunohistochemically, 17 of the 23 cases were positive for glial fiber acid protein (GFAP) and the remaining 6 cases were negative. The clinicopathologic features of childhood ependymomas, factors influencing prognosis and histologic classification are discussed.