title: A case of congenital supratentorial tumor: atypical teratoid/rhabdoid tumor or primitive neuroectodermal tumor?
abstract: Two embryonal CNS tumors, atypical teratoid/rabdoid tumor (AT/RT) and primitive neuroectodermal tumor (PNET), may be confused with each other and misdiagnosed. Here we report an infant with a congenital supratentorial tumor, which was detected by fetal MRI at 37 weeks gestation. On routine histological examination, the tumor was composed mainly of small undifferentiated cells, among which many rhabdoid cells and occasional sickle-shaped embracing cells were observed. No mesenchymal or epithelial areas were evident. Our impression was that the tumor was an atypical example of AT/RT. Immunohistochemically, almost all the tumor cells were strongly positive for vimentin. However, epithelial membrane antigen was notably negative, and most of the tumor cell nuclei were clearly positive for INI1. In addition, many tumor cells were positive for neurofilament protein. There were also occasional small areas containing many tumor cells positive for glial fibrillary acidic protein. Finally, a diagnosis of PNET, with a rhabdoid phenotype and expression of neuronal and glial markers, was made. In the present case, application of INI1 immunostaining was very helpful for distinguishing PNET from AT/RT.
authors.affiliation: Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan. yashiyashi100@bri.niigata-u.ac.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nishihira
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Tan
authors.forename: Junko
authors.initials: J
authors.lastname: Hirato
authors.forename: Junichi
authors.initials: J
authors.lastname: Yoshimura
authors.forename: Kenichi
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Fujii
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Takahashi
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D018242:Neuroectodermal Tumors, Primitive / Q000151:congenital / Q000378:metabolism / Q000473:pathology*; D011247:Pregnancy; D011296:Prenatal Diagnosis; D018335:Rhabdoid Tumor / Q000151:congenital / Q000378:metabolism / Q000473:pathology; D000071796:SMARCB1 Protein; D015173:Supratentorial Neoplasms / Q000151:congenital* / Q000378:metabolism / Q000473:pathology*; D013724:Teratoma / Q000151:congenital / Q000378:metabolism / Q000473:pathology*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors