11/120. Supratentorial primitive neuroectodermal tumours: diffusion-weighted MRI. We report the clinical and pathological findings of supratentorial primitive neuroectodermal tumours (PNETs). These are rare, poorly differentiated, highly malignant neoplasms occurring primarily in young individuals. They frequently show dissemination to the spinal cord and sometimes also beyond neuraxis. Preoperative radiological diagnosis is difficult, due to the nonspecific CT and MRI characteristics. Our findings indicate that diffusion-weighted imaging (DWI) can be used to show the solid portion of the tumour preoperatively and to monitor postsurgical recovery. We describe the MRI findings in three patients with histologically confirmed supratentorial PNET, focussing on the role of DWI for improving the specificity of radiological diagnosis. ( info) |
12/120. Immunohistochemical tenascin-C expression in paediatric supratentorial glioblastoma multiforme. tenascin-C (TN-C) plays an important part in the growth of neoplastic tissue, leading to new vessel development. TN-C has been assessed in adult glioblastoma multiforme (GBM) and has been evaluated as anti-neoplastic therapy. No studies have focused on this tissue in paediatric GBM. tissues were obtained from six paediatric supratentorial GBMs. immunohistochemistry was performed using a mouse antibody directed against human TN-C, and expression in tumour vasculature was described on the basis of TN-C immunoreactivity. The expression was minimal in three, moderate in two, and intense in one specimen. TN-C was not correlated with clinical history, neurological findings, or with tumour site. Although based on a limited number of patients, this study provides additional insights into tumour growth modulation and cytogenetic profile of paediatric GBM. The detailed understanding of events responsible for GBM growth is a prerequisite for the development of therapeutic modalities leading to improved prognosis and cure. ( info) |
13/120. Cyst wall enhancement in pilocytic astrocytoma: neoplastic or reactive phenomena. Cystic pilocytic astrocytomas (CPA) consist of a mural nodule and an accompanying cyst, which may prominently enhance on MRI after contrast administration. This raises the question whether an enhanced wall represents a tumor and thus should be resected together with the solid nodule, as radical tumor surgery is associated with better prognosis. Until now, no systematic histopathological examinations of cyst walls have been reported in correlation with MRI, intraoperative appearance and postoperative clinical and MRI follow-up. We present 3 patients with CPAs and brightly enhanced cyst walls on MRI. Because of the benign, transparent appearance of the cyst wall intraoperatively, it was biopsied but not resected, and only radical removal of the nodule and its immediate surroundings was performed. Separate specimens taken from the cyst wall showed no tumor. MRI performed annually, up to 48-56 months after surgery showed no recurrence of the cyst or the tumor. In such cases of CPA, we suggest that enhancement of cyst walls may represent reactive rather than tumoral tissue, and may be left intact without risking worse prognosis. Mechanisms leading to cyst wall enhancement and the optimal surgical treatment are discussed. ( info) |
14/120. Thalamic and hypothalamic tumors of childhood: endocrine late effects. Children who have received chemotherapy and radiation therapy for treatment of thalamic/hypothalamic tumors are at risk for late effects, specifically endocrine dysfunction. Evaluation of growth and pubertal development, thyroid function and integrity of the hypothalamic-pituitary-adrenal axis should be undertaken in a prospective manner. Issues of metabolic disturbances such as obesity, altered body composition/bone density as well as ultimate fertility also need to be addressed by ongoing prospective evaluations. ( info) |
15/120. High F-18 FDG uptake in a low-grade supratentorial ganglioma: a positron emission tomography case report. PURPOSE: Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (F-18 FDG) is used for the noninvasive monitoring and grading of primary brain tumors. Here the FDG uptake is positively correlated with the malignant extent of the lesion and thereby negatively correlated with patient survival. Little is known about the FDG PET features of primary brain tumors in children, such as mixed neuronal-glial tumors. methods: The authors describe a 13-year-old boy who had partial complex seizures since early childhood caused by a brain tumor in the left temporal lobe. RESULTS: Magnetic resonance and computed tomographic examinations yielded uncharacteristic results: mixed density, marked calcifications, little contrast enhancement, a nearly absent mass effect, and no edema. The FDG PET scan revealed a large hypermetabolic tumor, with a tumor: contralateral gray matter FDG uptake ratio of 1.45. In contrast to this intense hypermetabolism, the pathologic analysis after gross total resection revealed a low-grade ganglioglioma (WHO grade 1), which is usually associated with an excellent prognosis. CONCLUSIONS: Mixed neuronal-glial tumors such as gangliogliomas must be considered in making differential diagnoses by judging hypermetabolic FDG PET scans in young patients with brain tumors in the presence of uncharacteristic imaging features. ( info) |
16/120. Supratentorial haemangioblastoma: appearances on MR imaging. Haemangioblastoma is a rare, benign tumour of vascular origin which usually occurs in the posterior fossa. Supratentorial haemangioblastomas are exceptionally rare. In this report we present three cases of supratentorial haemangioblastoma with MRI findings. ( info) |
| Paragangliomas of the CNS are relatively rare. Cases of location in the pineal and pituitary glands, cerebellopontine angle, cauda equina and filum terminale are known. In our neurosurgical unit a 42-year-old male patient with a history of vertigo and a generalized seizure underwent an operation for a fronto-temporal tumour. The histological diagnosis was paraganglioma. ( info) |
18/120. Supracerebellar transtentorial approach to posterior temporomedial structures. The supracerebellar transtentorial (SCTT) approach, a modification of the infratentorial supracerebellar approach, facilitates simple and minimally invasive access to posterior temporomedial structures without requiring retraction of the temporal or occipital lobe. The SCTT approach was used in 16 patients over a 3-year period. Eleven patients harbored tumors confined to, or located mainly within, the posterior hippocampal formation, three patients harbored aneurysms (one ruptured posterior cerebral artery [PCA] aneurysm at the P2-P3 junction, one ruptured giant PCA [P2] aneurysm, and one giant basilar artery-superior cerebellar artery aneurysm), one patient had juvenile-type moyamoya disease, and one patient suffered from medically intractable epilepsy. In these patients, the SCTT approach enabled tumor removal, aneurysm clipping, and vascular bypass procedures. The authors' experience suggests that this approach can be used routinely in treating lesions in the posterior temporomedial region. ( info) |
19/120. Temporary response of localized intracranial mast cell sarcoma to combination chemotherapy. Cerebral involvement of systemic mastocytosis and intracranial sarcoma of myelogenic origin are well known entities. An 8-year-old girl with an isolated cerebral mast cell tumor is presented. Specific histopathologic stains were used to confirm the diagnosis detecting immunophenotype and proliferative activity. Treatment with irradiation, intrathecal cytarabine, and interferon-alpha2b did not induce regression whereas polychemotherapy did. Systemic combination chemotherapy led to marked transient tumor regression in this proliferating mast cell sarcoma in an unusual intracranial location. ( info) |
20/120. Supratentorial giant cell ependymoma. Ependymomas account for 3 to 9% of all neuroepithelial tumors and, although occurring most often within the ventricular system, they may arise from the extraventricular parenchyma as well. Several histologic patterns of these neoplasm are well known, but little attention has been devoted to a variant composed of giant elements. We describe the case of a 13-year-old girl experiencing a 3-month history of partial seizures in whom cranial magnetic resonance imaging showed an extraventricular, right parietotemporal neoplasm, adherent to the overlying dura mater. Histologic, immunohistochemical and ultrastructural findings were consistent with those of a high-grade ependymoma. The tumor was characterized by the presence of a major component of pleomorphic giant cells, as also seen in pleomorphic xantoastrocytoma, subependymal giant cell astrocytoma and glioblastoma multiforme. Similar elements have been described in two filum terminale and one supratentorial, intraventricular ependymoma, respectively. Histologic and evolutional data of those and of our own case suggest that isolated giant cells are not necessarily linked to a bad prognosis in ependymomas. ( info) |