title: Pediatric embryonal tumor with epithelial immunophenotype showing absence of hSNF5/INI1 expression.
abstract: METHODS
  A case of a histologically unclassified brain tumor in a 32-month-old boy is reported. He presented with vomiting, appetite loss, and right motor weakness. MR images revealed a huge mass in the left frontoparietal region that was enhanced after the administration of Gd-DTPA. The mass was removed three times because of its recurrence.
  
  
  RESULTS
  Histologically, the tumor was composed largely of small-undifferentiated round cells without any patterns of differentiation. Immunohistochemically, the tumor cells were positive for cytokeratin and focally for epithelial membrane antigen (EMA). Glial fibrillary acidic protein (GFAP), S-100 protein and neuronal markers were negative. Electron microscopic investigations demonstrated no evidence of specific differentiation. MIB-1 staining index was 10-40%. The origin of the tumor was not detected. Expression of the hSNF5/INI1 of this tumor was not detected by reverse transcription-polymerase chain reaction (RT-PCR). The patient has been in a good condition for 7 years after the first operation.
  
  
  CONCLUSIONS
  Based on the immunohistochemical findings, the tumor was descriptively diagnosed as an embryonal tumor with an epithelial immunophenotype. The hSNF5/INI1 gene has recently been reported to act as a tumor suppressor in atypical teratoid/rhabdoid tumors. The hSNF5/INI1 gene may lead to tumorigenesis in this case.
authors.affiliation: Department of Neurosurgery, Shinshu University School of Medicine, Asahi 3-1-1, Matsumoto 390-8621, Japan. skeiichi@hsp.md.shinshu-u.ac.jp
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sakai
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shigeta
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Ogiso
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hongo
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Takanori
authors.initials: T
authors.lastname: Hirose
mesh_terms: D015415:Biomarkers; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism*; D002675:Child, Preschool; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D019786:Gadolinium DTPA; D015972:Gene Expression Regulation, Neoplastic; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007633:Keratins / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D018396:Mucin-1 / Q000378:metabolism*; D010296:Parietal Lobe / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D000071796:SMARCB1 Protein; D014057:Tomography, X-Ray Computed / Q000379:methods; D014157:Transcription Factors
chemical_list: D015415:Biomarkers; C400901:CAM 5.2 antigen; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D018396:Mucin-1; D012333:RNA, Messenger; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors; D007633:Keratins; D019786:Gadolinium DTPA