The human Ras association domain family 1A (RASS-F1A) gene, recently isolated from the lung and breast tumor suppressor locus 3p21.3, is highly methylated in primary lung, breast, nasopharyngeal and other tumors, and re-expression of RASSF1A suppresses the growth of several types of cancer cells. Epigenetic inactivation of RASSF1A by promoter hypermethylation is also important in the development of several human cancers. The methylation status of the promoter region of RASSF1A was analysed in primary brain tumors and glioma cell lines by methylation-specific polymerase chain reaction. In primary brain tumors, 25 of 46 (54.3%) gliomas and five of five (100%) medulloblastomas showed RASSF1A methylation. In benign tumors, only one of 10 (10%) schwannomas and two of 12 (16.7%) meningiomas showed RASSF1A methylation. The RASSF1A promoter region was methylated in all four glioma cell lines. RASSF1A was re-expressed in all methylated cell lines after treatment with the demethylating agent 5-aza-2 0 -deoxycytidine. Methylation of the promoter CpG islands of the RASSF1A may play an important role in the pathogenesis of glioma and medulloblastoma.
Adult cerebellar high-grade gliomas (HGG) are rare and their molecular basis has not been fully elucidated. Although a diffuse midline glioma H3 K27M-mutant, a recently characterized variant of HGG, was reported to occasionally occur in the cerebellum, adult cases were rarely tested for this mutation; only five mutant cases have been reported to date. It currently remains unknown whether H3 K27M-mutant cerebellar gliomas share common histological features or have a uniformly dismal prognosis. In the present study, we assessed the prevalence of histone H3 K27M mutations in ten adult cerebellar HGG, identifying two H3F3A-mutant cases. One case was a 70-year-old female with a cystic lesion. Histologically, the tumor was considered to be glioblastoma; however, a part of the tumor exhibiting low proliferative activity appeared to be consistent with long-standing H3 K27M-mutant tumors in the literature. Another case was a 69-year-old male. The tumor showed a distinct circumscribed histology with minimal astrocytic differentiation, suggesting a nosological issue in the diagnosis of diffuse midline glioma. More cerebellar tumors need to be tested for H3 K27M mutations to clarify the clinical and histopathological spectra of this tumor.
Superficial siderosis is a rare condition caused by hemosiderin deposits in the central nervous system (CNS) due to prolonged or recurrent low-grade bleeding into the cerebrospinal fluid (CSF). CNS tumor could be one of the sources of bleeding, both pre- and postoperatively. We report an extremely rare case of superficial siderosis associated with purely third ventricle craniopharyngioma, and review previously reported cases of superficial siderosis associated with CNS tumor. A 69-year-old man presented with headache, unsteady gait, blurred vision, and progressive hearing loss. Brain magnetic resonance (MR) imaging with gadolinium revealed a well enhanced, intraventricular mass in the anterior part of the third ventricle. T2*-weighted gradient echo (GE) MR imaging revealed a hypointense rim around the brain particularly marked within the depth of the sulci. Superficial siderosis was diagnosed based on these findings. The tumor was diffusely hypointense on T2*-weighted GE imaging, indicating intratumoral hemorrhage. The lateral ventricles were dilated, suggesting hydrocephalus. [18F]fluorodeoxyglucose positron emission tomography revealed increased uptake in the tumor. The whole brain surface appeared dark ocher at surgery. Histological examination showed the hemorrhagic tumor was papillary craniopharyngioma. His hearing loss progressed after removal of the tumor. T2*-weighted GE MR imaging demonstrated not only superficial siderosis but also diffuse intratumoral hemorrhage in the tumor. Superficial siderosis and its related symptoms, including hearing loss, should be considered in patients with hemorrhagic tumor related to the CSF space. Purely third ventricle craniopharyngioma rarely has hemorrhagic character, which could cause superficial siderosis and progressive hearing loss.
Objective The supplementary motor area (SMA) is important for the prediction of post-operative symptoms after surgical resection of gliomas. We investigated the relationships between clinical factors and the resection range of SMA gliomas, and the post-operative neurological symptoms. Methods We retrospectively studied 18 consecutive surgeries for gliomas involving the SMA proper performed in 13 patients. Seven cases were recurrence of the tumour. Clinical factors and details of specific resection of the SMA proper (resection of posterior part, medial wall) and cingulate motor area (CMA) were examined. Results Eight cases suffered new post-operative neurological deficits. Six of these eight cases had transient deficits. Permanent deficits persisted in two cases with partial weakness or paresis, after rapid improvement of post-operative global weakness or hemiplegia, respectively. The risk of post-operative neurological deficits was not associated with the resection of the posterior part of the SMA proper or the CMA, but was associated with resection of the medial wall of the SMA proper. Surgery for recurrent tumour was associated with post-operative neurological deficits. The medial wall was frequently resected in recurrent cases. Discussion The frequency of post-operative neurological symptoms, including SMA syndrome, may be higher after resection of the medial wall of the SMA proper compared with the resection of only the lateral surface of the SMA proper.
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