1/6. Congenital disseminated malignant rhabdoid tumor and cerebellar tumor mimicking medulloblastoma in monozygotic twins: pathologic and molecular diagnosis.Malignant rhabdoid tumors are highly aggressive childhood tumors. Recently, all of the malignant rhabdoid tumors, whatever their location, have been related to the inactivation of the hSNF5/INI1 gene. A subset of cerebral tumors, associated with malignant rhabdoid tumors or isolated ones arising in siblings, showed similar molecular alterations. We report for the first time in monozygotic twins a congenital disseminated malignant rhabdoid tumor in one twin and a cerebellar tumor mimicking a medulloblastoma in the other. Molecular analysis revealed similar alterations for both tumors: a deletion of exon 7 of the hSNF5/INI1 gene in one allele, and a point mutation in the same exon in the other, suggesting a common genetic pathway. Analysis of constitutional dna revealed a germline mutation. These findings are in favor of a common etiology for rhabdoid tumor and a subset of brain tumors developing in infancy.- - - - - - - - - - ranking = 1keywords = rhabdoid (Clic here for more details about this article) |
2/6. A unique occurrence of a cerebral atypical teratoid/rhabdoid tumor in an infant and a spinal canal primitive neuroectodermal tumor in her father.This report describes the clinical, pathological, immunohistochemical and genetic data of two rare malignant neoplasms of the central nervous system (CNS)--a cerebral atypical teratoid/rhabdoid tumor (AT/RT) in a 5-month-old girl and a spinal canal primitive neuroectodermal tumor (PNET) in her father. Despite aggressive treatment, both tumors were fatal, displaying extensive local recurrence and diffuse neoplastic dissemination. The paraffin-embedded tumor tissue samples were analyzed using a dual-color FISH with a locus specific LSI22q (BCR) probe. In the AT/RT tissue, a loss of BCR locus was observed in a significant proportion of the cells in contrast to the PNET specimen where the majority of nuclei did not reveal any loss of the BCR region. No mutations in exon 5 and no changes in SNP of intron 5 of hSNF/INI1 gene were found. In addition, analysis of loss of heterozygosity (LOH) was performed using a panel of 15 microsatellite markers of chromosome 22. No LOH were found in both tumor tissues. In both cases no constitutional mutations of gene TP53 were found. Analysis of the TP53 mutations in the tumor tissues revealed that the PNET, not the AT/RT tumor, was homozygous for a missense mutation at codon 175 (CGC ==> CAC). Thus, our findings emphasize the genetic differences between the two specimens and suggest that the occurrence of these two aggressive tumors of CNS in one family could be coincidental.- - - - - - - - - - ranking = 0.55555555555556keywords = rhabdoid (Clic here for more details about this article) |
3/6. Cytogenetic characteristics of a malignant rhabdoid tumor arising from the paravertebral region. A case report.The pathological and cytogenetic features of an extrarenal malignant rhabdoid tumor (MRT) arising from the paravertebral region in an infant were investigated. The patient died 4 months after diagnosis, due to aggressive tumor progression. The tumor was composed of medium-sized round cells with cytoplasm containing eosinophilic inclusions, which ultrastructurally were composed of densely packed whorled intermediate filaments. Flow-cytometric analysis of the tumor cells revealed a diploid pattern. Amplification of the N-myc oncogene was not identified. Immunohistologically, the inclusion bodies showed a positive reaction with antiserum against vimentin. The tumor cells were not reactive with antiserum against epithelial membrane antigen, anti-keratin (polyclonal) or cytokeratin (monoclonal, CK1), but did react with 5H10, an antiserum established from human sarcomatous Wilms' tumor. This case is discussed with reference to the literature on extrarenal MRT, placing stress on the histogenesis of this tumor.- - - - - - - - - - ranking = 0.55555555555556keywords = rhabdoid (Clic here for more details about this article) |
4/6. Establishment and characterization of a cell line (Wa-2) derived from an extrarenal rhabdoid tumor.A new human cell line (Wa-2) derived from an extrarenal rhabdoid tumor has been established. The cell line grows as a monolayer consisting of round- and spindle-shaped cells. Injection of cells into nude mice results in the growth of solid tumors within 2 wk of inoculation. These solid tumors have the microscopic appearance similar to that of the original tumor from which the cell line was derived. Moreover, the tumor cells have all the features of rhabdoid tumors, including the intracytoplasmatic hyaline globules, large prominent nucleoli, and inclusion bodies made up of whorls of fibrillary material. Transplanted tumor cells stain positive for vimentin, cytokeratin, actin, and desmin and negative for myoglobin and neuron-specific enolase. karyotyping of the cell line at different passages and cells derived from the transplant tumors consistently revealed a diploid number of chromosomes with a reciprocal translocation between chromosomes 18 and 22 [t(18;22) (q21;p11.2)]. In fibroblasts derived from the patient, no translocation could be found. Culturing the cells in the presence of 1-beta-D-arabinofuranosylcytosine induces differentiation, characterized by the outgrowth of neuron-like processes and the morphological appearance of cells similar to neuroblasts. Southern blot analysis showed no amplification of the N-myc oncogene. Since no published cell line derived from rhabdoid tumors exists, this cell line should be helpful to further elucidate the biology and histological origin of the malignant rhabdoid tumor.- - - - - - - - - - ranking = 0.88888888888889keywords = rhabdoid (Clic here for more details about this article) |
5/6. Paravertebral malignant rhabdoid tumor in an adult. A case report with immunocytochemical study.A case of paravertebral malignant rhabdoid tumor in a 59-year-old man is described. The location of the tumor and age of the patient appear to be unique. The clinical evolution was aggressive and resulted in the death of the patient. The tumor exhibited the light microscopic features of a typical rhabdoid tumor. It was composed of poorly differentiated round or polygonal cells with acidophilic glassy inclusions and vesicular nuclei exhibiting prominent nucleoli. immunohistochemistry revealed the coexpression of cytokeratin and vimentin in neoplastic cells.- - - - - - - - - - ranking = 0.66666666666667keywords = rhabdoid (Clic here for more details about this article) |
6/6. Malignant rhabdoid tumor of the thoracic spine.A case of malignant rhabdoid tumor of the spine and a description of its CT findings are presented. The CT demonstrated a heterogeneous contrast enhancing epidural mass associated with severe bony destruction of the adjacent vertebra and cord compression.- - - - - - - - - - ranking = 0.55555555555556keywords = rhabdoid (Clic here for more details about this article) |