title: Atypical Teratoid/Rhabdoid Tumor (AT/RT) Arising From    Ependymoma: A Type of AT/RT Secondarily Developing   From Other Primary Central Nervous System Tumors.
abstract: Atypical teratoid/rhabdoid tumors (AT/RT) are rare, aggressive, embryonal brain tumors that occur most frequently in very young children; they are characterized by rhabdoid cells and loss of INI1 protein nuclear expression. Here, we report the case of a 24-year-old man with a left frontal lobe tumor that was composed mainly of rhabdoid cells showing loss of INI1 nuclear reactivity and polyphenotypic immunohistochemical expression, with a small INI1-positive component of ependymoma. Array comparative genomic hybridization separately conducted for each histologically distinct component revealed 22 shared identical copy number alterations, including loss of heterozygosity of chromosome 22q containing the INI1 locus. Furthermore, we found the C11orf95-RELA fusion gene, the genetic hallmark of supratentorial ependymomas, not only in the ependymoma component but also in the AT/RT component by fluorescence in situ hybridization analysis, suggesting that the AT/RT cells secondarily progressed from the preexisting ependymoma cells. A second genetic inactivating event in the INI1 gene was not detected in the AT/RT component. There are several reported cases of AT/RT (or INI1-negative rhabdoid tumors) arising in the setting of other primary brain tumors (gangliogliomas, pleomorphic xanthoastrocytomas, and high-grade gliomas), but the present case
authors.forename: Sumihito
authors.initials: S
authors.lastname: Nobusawa
authors.forename: Junko
authors.initials: J
authors.lastname: Hirato
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Sugai
authors.forename: Naoki
authors.initials: N
authors.lastname: Okura
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamazaki
authors.forename: Seiji
authors.initials: S
authors.lastname: Yamada
authors.forename: Hayato
authors.initials: H
authors.lastname: Ikota
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nakazato
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yokoo
mesh_terms: D016543:Central Nervous System Neoplasms / Q000378:metabolism / Q000473:pathology*; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis / Q000235:genetics; D056915:DNA Copy Number Variations; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D004806:Ependymoma / Q000473:pathology*; D006801:Humans; D008297:Male; D011506:Proteins / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000096:biosynthesis / Q000235:genetics; D018335:Rhabdoid Tumor / Q000378:metabolism / Q000473:pathology*; D000071796:SMARCB1 Protein; D015173:Supratentorial Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D013724:Teratoma / Q000378:metabolism / Q000473:pathology*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D055815:Young Adult
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D011506:Proteins; D048493:Proto-Oncogene Proteins B-raf; D000071796:SMARCB1 Protein; D014157:Transcription Factors; C585140:ZFTA protein, human; C513266:SMARCB1 protein, human; C482119:BRAF protein, human