1/61. Severe Lhermitte-Duclos disease with unique germline mutation of PTEN.Germline mutations in the PTEN gene have recently been identified in some individuals with Cowden disease (CD), Lhermitte-Duclos disease (LDD), and Bannayan-Zonana syndrome. We report on a patient with CD and LDD in whom a unique de novo germline missense mutation is present in the PTEN gene. Direct sequence analysis detected a transitional change (T-->C) at nucleotide 335, resulting in substitution of the amino acid proline for leucine. The mutation is in exon 5, which has been proposed as a "hot-spot" for germline mutations. Comparison of this patient's clinical course with the previously reported cases of CD and LDD shows more extensive and more severe clinical findings than reported previously. Findings in this patient contribute to the current understanding of germline PTEN mutations and clinical outcome.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
2/61. HPV in situ hybridization with catalyzed signal amplification and polymerase chain reaction in establishing cerebellar metastasis of a cervical carcinoma.We report an unusual case of cerebellar metastasis from a cervical adenosquamous carcinoma in which molecular techniques assisted in establishing the correct diagnosis. The patient was a 43-year-old woman with surgically unresectable cervical carcinoma diagnosed 2 years before presenting with neurological symptoms. A magnetic resonance imaging scan showed a large, enhancing cerebellar lesion with significant brain stem compression. The excised cerebellar tumor resembled a small cell carcinoma and was initially not thought to be a metastasis from the cervical adenosquamous carcinoma. in situ hybridization with catalyzed signal amplification and polymerase chain reactions with primers specific for human papilloma virus (HPV) types 16 and 18 were used to determine the relationship between the cervical and the cerebellar neoplasms. A positive signal was present in the nuclei of both neoplasms by in situ hybridization using HPV16/18 dna probes. polymerase chain reaction revealed the presence of HPV-18 DNA sequences in the cervical and cerebellar neoplasms confirming that the cerebellar neoplasm was a metastasis from the cervical primary.- - - - - - - - - - ranking = 44275.778063606keywords = amplification (Clic here for more details about this article) |
3/61. Signet-ring cell ependymoma: case report with implications for pathogenesis and differential diagnosis.We describe light microscopic, immunohistochemical and ultrastructural features of a signet-ring cell ependymoma (WHO grade II) identified in a surgically resected left cerebellar cystic tumor from a 64-year-old man. Part of the tumor showed clear-cell differentiation. Immunohistochemical coexpression of glial fibrillary acidic protein and epithelial membrane antigen, characteristic of ependymoma, was detected in both components. Sinuous intermediate junctions, cytoplasmic lumina, and scant astroglial filaments were demonstrated by electron microscopy. Signet-ring cell change was shown to be induced by disproportionate cavitation of either microvillus-bearing cytoplasmic lumina or microrosettes. The staining qualities of clear cells were mainly due to paucity and degeneration of subcellular organelles. Therefore, signet-ring cell ependymomas represent a unique anomaly of intra- and extracellular compartmentalization to be distinguished from various unrelated forms of cytoplasmic volume increase, resulting in an optically similar "empty" appearance of tumor cells. As a clinically relevant consequence, signet-ring cell ependymoma must be included in the differential diagnosis of primary or metastatic neoplasms of the central nervous system, having in common a phenotype characterized by overdeveloped optically lucent cell bodies.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
4/61. Oncogene amplification in medulloblastoma: analysis of a case by comparative genomic hybridization and fluorescence in situ hybridization.We describe amplification of the MYCC oncogene in a medulloblastoma with aggressive clinical behavior. The patient was a six year old boy who underwent gross total surgical excision of a cerebellar tumor. Despite chemotherapy and total neuraxis radiation, the clinical course was one of relentless progression, with extensive subarachnoid spread and death within eight months of presentation. The pathological features were consistent with the recently described, "large cell variant" of medulloblastoma. Tumor cells exhibited large vesicular nuclei, prominent nucleoli and strong immunoreactivity for synaptophysin. polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) assay revealed no evidence of MYCN amplification or 1p deletion in the tumor. FISH analysis revealed evidence of MYCC amplification in the 20- to 30-fold range. Comparative genomic hybridization (CGH) revealed regions of gains and amplification in three locations, with gains of chromosome 7, amplification of 8q24 (corresponding to the MYCC locus) and gains of the long arm of chromosome 17 (suggestive of isochromosome 17q). While conventional karyotypic analysis was not successful in the present case, CGH provided invaluable information about gene amplification and losses/gains of chromosomes and chromosomal regions. Thus, CGH is a powerful technique applicable to frozen or paraffin-embedded material which helps to ascertain the presence of gene amplification even without prior knowledge of the gene to be tested.- - - - - - - - - - ranking = 97406.711739934keywords = amplification (Clic here for more details about this article) |
5/61. DNA-based diagnosis of the von Hippel-Lindau syndrome.PURPOSE: To evaluate the etiology of a unilateral hemangioblastoma noted in a male with a family history remarkable only for spine surgery in the proband's father. methods: Genomic DNA was isolated from peripheral blood of family members, and the three exons of the von Hippel-Lindau gene were examined for mutations by direct sequencing. RESULTS: A three base pair (bp) deletion in exon 1 of the VHL gene was found in the father and both sons. This in-frame deletion results in the loss of a phenylalanine residue from the von Hippel-Lindau protein product, at amino acid position 76. CONCLUSION: Genetic screening has confirmed that von Hippel-Lindau syndrome is responsible for the hemangioblastoma in the proband. magnetic resonance imaging scans performed as a consequence of these results indicated spinal tumors present in the father and tumors present in the cerebellum of the proband's sibling. As close, lifelong follow-up is warranted with this disease, this case demonstrates the value of DNA testing in patients with ocular findings consistent with von hippel-lindau disease in the absence of a recognized family history.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
6/61. Multiple genomic alterations including N-myc amplification in a primary large cell medulloblastoma.The large cell (LC) subtype is a recently described histologic variant of medulloblastoma (Mb) associated with a rapid and aggressive clinical course. We describe the genomic profile of a LC-Mb tumor obtained from a patient who developed recurrent and fulminant disease despite 'good-risk' features at diagnosis and state- of-the-art multidisciplinary therapy. The tumor sample was analyzed using comparative genomic hybridization (CGH) and complementary molecular approaches. CGH revealed amplicons at chromosome bands 2p24-25, 2q12-22, and 17p11; losses of chromosomes 11q and 18; and low-level gains of 3q, 11p, 13q and 14q. Southern blot analysis confirmed N-myc amplification. No evidence of p53 mutation was detected. The genomic profile of this LC-Mb tumor sample revealed a distinctive pattern of genetic alterations including amplification of N-myc and anonymous oncogenes at chromosome bands 2q12-22 and 17p11. These genomic abnormalities are uncommon in other subtypes of Mb.- - - - - - - - - - ranking = 53130.933676328keywords = amplification (Clic here for more details about this article) |
7/61. herpes simplex encephalitis occurring after chemotherapy, surgery, and stereotactic radiotherapy for medulloblastoma.Reactivation of latent herpes simplex virus (HSV) in the trigeminal ganglion most commonly gives rise to recurrent herpes labialis and rarely to herpes simplex encephalitis. The mechanisms underlying reactivation of latent trigeminal HSV are complex. Here we report the case history of a 25-year-old woman who developed a fatal, bilateral necrotizing destructive temporal lobe lesion following surgical removal of a cerebellar medulloblastoma and combined radiotherapy and chemotherapy for recurrent tumor. Neuropathologic examination of the brain revealed minimal inflammatory changes, but immunohistochemistry was positive for HSV protein, and HSV deoxyribonucleic acid (DNA) was recovered from formalin-fixed paraffin-embedded brain tissue. The temporal proximity of the surgery, chemotherapy, and radiotherapy to the onset of disease suggests that these factors may have acted as triggers that precipitated conversion of latent HSV to overt HSV.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
8/61. comparative genomic hybridization of medulloblastomas and clinical relevance: eleven new cases and a review of the literature.Medulloblastomas are highly malignant primitive neuroectodermal tumors of the cerebellum that display a wide variety of histopathological patterns. However, these patterns do not provide an accurate prediction of clinical-biological behavior and no satisfactory morphological grading system has ever been presented. Genetic alterations may provide additional diagnostic information and allow clinically relevant subgrouping of primitive neuroectodermal tumors. We examined 10 medulloblastomas and one medulloblastoma cell line. One amplification site on chromosome 8q24 was detected in the cell line corresponding to the known amplification of the c-myc gene in this cell line. The gain of 2p21-24 in two tumors was shown to represent amplification of the N-myc gene by Southern blot hybridization and fluorescence in situ hybridization. The data show that the isochromosome 17 can be recognized using comparative genomic hybridization (CGH) by the typical combination of loss of 17p combined with gain of 17q. No specific pattern of genetic alterations could be linked to the clinical behavior of the tumors. We have compared our results with previous CGH studies on medulloblastomas.- - - - - - - - - - ranking = 26565.466838164keywords = amplification (Clic here for more details about this article) |
9/61. Cerebellar liponeurocytoma: immunohistochemical and ultrastructural study of a case.The clinical, histopathological, and ultrastructural features of a cerebellar liponeurocytoma are reported. The tumor, a 3-cm mass localized in the right cerebellar hemisphere, was resected from a 61-year-old man clinically presenting with symptoms of intracranial hypertension. The lesion was composed of small, in some areas closely packed, medulloblastoma-like cells with prominent areas of lipidization phenomena. Moreover, mitoses, cellular atypia, and numerous vascular structures were focally observed. Glial and neuronal differentiation was immunohistochemically noted (glial fibrillary acidic protein, synaptophysin, neurofilaments, and neuron-specific enolase positivity). The p53 oncoprotein was detected in the majority of neoplastic cells and a moderate proliferation activity, evaluated by Mib-1 antibody, was focally appreciated. Ultrastructural study did not show evident neuritic processes, synapses, or dense core neuroendocrine granules. This cerebellar tumor previously called lipidized medulloblastoma and recently renamed cerebellar liponeurocytoma is considered an adult neoplasm with excellent prognosis histologically presenting prominent lipidized areas and, at the immunohistochemical and ultrastructural level, both glial and neuronal differentiation. The present study provides the first description of a less differentiated and histologically more aggressive form of this unusual tumor.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
10/61. Large cell/anaplastic medulloblastomas and medullomyoblastomas: clinicopathological and genetic features.OBJECT: medulloblastoma is the most common malignant central nervous system neoplasm found in children. A distinct variant designated large cell/anaplastic (LC/A) medulloblastoma is characterized by frequent dissemination of cerebrospinal fluid (CSF) at presentation and a more aggressive clinical course. The authors report on their examination of the clinicopathological and genetic features of seven such cases encountered at their institution. methods: Eighty cases of medulloblastomas were reviewed and seven (8.8%) of these were believed to fit the histological and immunohistochemical criteria for LC/A medulloblastoma. In three cases (43%) either desmoplastic or classic medulloblastoma was the underlying subtype, and in two cases (28%) the LC/A tumor was found within the setting of medullomyoblastoma. fluorescence in situ hybridization was used in six of the seven cases to characterize the presence of isochromosome 17q, deletion of chromosome 22q (a deletion characteristically found in atypical teratoid/rhabdoid tumors), and c-myc amplification. The patients' clinical histories revealed CSF dissemination in all cases and lymph node metastasis in one case. Isochromosome 17q was found in five (83%) of six cases. Evidence of chromosomal gains indicated aneuploidy in three tumors (50%), and amplification of c-myc was found in three tumors (50%). No 22q deletions were encountered. CONCLUSIONS: A high percentage of LC/A medulloblastomas arise within a background of typical medulloblastomas or medullomyoblastomas. As is the case in conventional medulloblastomas, the presence of 17q is a common early tumorigenic event; however, in a significant percentage of specimens there is also evidence of aneuploidy and/or amplification of c-myc. These findings indicate that LC/A morphological characteristics reflect a more advanced tumor stage than that found in pure medulloblastomas or in typical medullomyoblastomas.- - - - - - - - - - ranking = 26565.466838164keywords = amplification (Clic here for more details about this article) |
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