INI1 mutations in meningiomas at a potential hotspot in exon 9.
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Rhabdoid tumours have been shown to carry somatic mutations in the INI1 (SMARCB1/hSNF5) gene. A considerable fraction of these tumours exhibit allelic losses on chromosome 22. Allelic loss on 22q also is characteristic for meningiomas, however most of these alterations are considered to be associated with mutations of the NF2 gene. We examined a series of 126 meningiomas for alterations in the INI1 gene. Four identical somatic mutations in exon 9 were detected resulting in an exchange of Arg to His in position 377 of INI1. Our observations were reproduced both by using DNA from a new round of extraction and by employing overlapping primers. This mutational hotspot therefore appears to be an important target in the formation of a fraction of meningiomas. In addition, 4 novel polymorphisms of INI1 were characterized. Our data indicate that the INI1 is a second tumour suppressor gene on chromosome 22 that may be important for the genesis of meningiomas. (+info)
Intraoperative radiation therapy as an adjunctive therapy for huge and highly vascular parasagittal meningiomas.
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This case presents a 34-year-old man who had a huge parasagittal meningioma. Initial treatment consisted of preoperative external carotid artery embolization and partial tumor resection. During the resection, we found that the tumor invaded the adjacent calvarium, and due to massive hemorrhage, total removal of the tumor was impossible. The patient was treated with intraoperative radiation therapy (IORT) (25 Gy via 16 MeV) as an adjunctive therapy. Eight months after IORT, we were able to remove the tumor completely without surgical difficulties. IORT can be considered an useful adjunctive therapy for the superficially located, huge, and highly vascular meningioma. (+info)
Novel tankyrase-related gene detected with meningioma-specific sera.
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In many meningiomas, alterations of chromosome 22 can be found, and the NF2 (neurofibromatosis type 2) gene, in particular, is of great interest as a putative gene involved in meningioma. Because the NF2 gene is not mutated in all meningiomas, additional genes may be involved. Instead of looking for alterations directly at the DNA level, we used the immune response of meningioma patients to identify immunogenic antigens that may be associated with the disease. We screened a fetal brain cDNA expression library with sera pools from different patients bearing meningioma classified according to the three WHO grades, using the serological identification of antigens by recombinant expression cloning immunological screening method. Here, we report the finding of a new tankyrase-related protein. We found 16 overlapping clones with homologies to tankyrase when we screened the library with the common-type meningioma sera pool and 2 such clones when we screened the library with the atypical meningioma sera. The anaplastic meningioma sera did not identify any tankyrase-related clones. We tested some of the newly identified clones with 13 single sera, 6 of which (37.5%) reacted positively with the tankyrase-related clones. In addition, we screened the tankyrase-related clone with six sera pools from individuals without obvious disease. Although 1 of 24 (4.2%) normal sera reacted with the tankyrase-related clone, we found a striking difference in the frequency of reactivity to this clone by sera from patients bearing tumors corresponding to the three WHO meningioma grades; common-type sera was the most frequently reactive. Northern blot analysis demonstrates expression of the novel tankyrase gene in two common-type meningiomas from patients with immune response. (+info)
PS6K amplification characterizes a small subset of anaplastic meningiomas.
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PS6K, a putative oncogene mapped to chromosome 17q23, encodes a serine/threonine kinase, which phosphorylates ribosomal subunit 6 and is part of the insulin receptor signal transduction pathway involved in the regulation of messenger RNA translation, protein synthesis, cell cycle progression, and cell size. Comparative genomic hybridization studies have detected 17q23 amplifications in a subset of meningiomas, particularly those with aggressive histologic features. PS6K amplifications have been reported in breast cancer, another hormonally driven neoplasm. We assessed PS6K dosage in 94 archival paraffin-embedded meningiomas using dual-color fluorescence in situ hybridization. We found high-level PS6K amplifications in 3 of 22 anaplastic grade III meningiomas. Amplification was confirmed by differential polymerase chain reaction in 1 of these cases. In contrast, no amplifications were identified in 37 benign (grade I) and 35 atypical (grade II) meningiomas. To our knowledge, this represents the first report of gene amplification in primary human meningiomas. Given its exclusive association with anaplastic meningiomas, PS6K amplification likely occurs during the malignant progression of a small subset of anaplastic tumors. Further studies are needed to map the 17q23 amplicon to determine whether additional genes in this region are amplified in high-grade meningiomas. (+info)
Hemifacial spasm due to cerebellopontine angle meningiomas--two case reports.
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A 54-year-old female and a 49-year-old female presented with complaints of hemifacial spasm. Both patients underwent surgery to remove cerebellopontine angle meningiomas. In one case, no vascular compression was observed at the root exit zone. The tumor was removed subtotally leaving residual tumor adhered to the lower cranial nerves. The hemifacial spasm disappeared immediately after the operation. The residual tumor was treated using gamma knife radiosurgery. In the other case, the root exit zone of the facial nerve was compressed by both the tumor and anterior inferior cerebellar artery and the tumor was removed totally. Postoperatively, the hemifacial spasm disappeared, but the patient suffered facial nerve paresis and deafness that was probably due to intraoperative manipulation. However, the facial nerve paresis gradually improved. Cerebellopontine angle meningioma with hemifacial spasm must be treated by surgical resection limited to preserve cranial nerve function. Subtotal removal with subsequent radiosurgery to treat the remaining tumor tissue is one option for the treatment of cerebellopontine angle meningioma. (+info)
A 69-year-old female presented with a rare intracranial meningeal malignant fibrous histiocytoma (MFH). The neuroimaging appearance of this tumor was very similar to parasagittal meningioma. The tumor was grossly totally removed, and local irradiation of 50 Gy was performed. The histological diagnosis was MFH. The patient recovered from the preoperative deficits, and no recurrence was observed by 27 months after surgery. (+info)
Prostaglandin D synthase (beta-trace) in meningeal hemangiopericytoma.
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The level of prostaglandin D synthase (PGDS), a major protein constituent of cerebrospinal fluid (CSF), is altered in various brain diseases, including meningitis. However, its role in the brain remains unclear. PGDS is mainly synthesized in the arachnoid cells, the choroid plexus and oligodendrocytes in the central nervous system. Among brain tumors, meningiomas showed intense immunoreactivity to PGDS in the perinuclear region. Thus, PGDS has been considered a specific cell marker of meningioma. In this study, we examined 25 meningeal hemangiopericytomas (HPCs) and found that 16 of the tumors (64%) showed immunoreactivity for PGDS in the perinuclear region. For comparison, 15 meningiomas, 14 soft-tissue HPCs, 1 mesenchymal chondrosarcoma, 3 choroid plexus papillomas, and 7 oligodendrogliomas were also examined. Meningiomas showed positive immunoreactivity for PGDS in 13 cases (80%). Except for one case located at the sacrum, none of the other soft-tissue HPCs showed immunostaining for PGDS. Mesenchymal chondrosarcoma arises in the bones of the skull, and its histological pattern resembles that of HPC; however, it showed no immunoreactivity for PGDS. Neither choroid plexus papillomas nor oligodendrogliomas were immunopositive for PGDS. These findings suggest that meningeal HPCs may have a unique molecular phenotype that is distinct from that of the soft-tissue HPCs. The origin of meningeal HPCs may be more closely related to the arachnoid cells. (+info)
Diffuse leptomeningeal malignant histiocytosis in the brain and spinal cord of a Tibetan Terrier.
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An 8-year-old male Tibetan Terrier showed prolonged astasia, complete paralysis, ticlike signs, and seizure and died 2 months after the onset of symptoms. Histopathologically, there was moderate to severe infiltration of pleomorphic histiocytic mononuclear cells bilaterally in the basiarachnoidal and ventricular areas of the brain. The spinal dura mater, arachnoidal space, and leptomeninges were also affected by infiltrative proliferation of these mononuclear cells. The infiltrating cells had the morphologic characteristics of histiocytes but exhibited moderate pleomorphism and atypia, with abundant mitotic figures. With immunohistochemistry and lectin histochemistry, most of the infiltrating cells were positive for lysozyme and lectin RCA-1 and negative for glial fibrillary acid protein, suggesting that they were of monocytic/histiocytic-origin. Positive proliferating cell nuclear antigen immunostaining demonstrated that most nuclei of the histiocytic cells were in the S phase of the cell cycle, consistent with a proliferating population of cells. Based on these findings, the case was diagnosed as diffuse leptomeningeal malignant histiocytosis. (+info)