title: Immunohistochemical study as a tool in differential diagnosis of pediatric malignant rhabdoid tumor.
abstract: Malignant rhabdoid tumors (MRTs) are aggressive childhood neoplasms, occurring mainly in the kidney and brain. We describe 2 unusual cases of extrarenal and noncranial location (liver and soft tissue with dissemination) mimicking hepatoblastoma, neuroblastoma or Ewing sarcoma. Both cases revealed a polyphenotypic profile, combined with cytokeratin, vimentin, and CD99 expression. INI1/BAF-47 showed negative protein nuclear expression in both cases, suggesting a diagnosis of MRT. An extensive immunohistochemical panel was performed to exclude pediatric tumors reminiscent of MRT. The genetic studies failed to detected MYCN amplification, 11q23 deletion, and EWS break-apart positivity. No alterations of 22q integrity were demonstrated with the probes used for the study (N25 Di George/22q11.2, 22qter, and EWS/22q12). We discuss the differential diagnosis in pediatric polyphenotypic tumors (Wilms tumor, neuroblastoma, desmoplastic small round cell tumor, and Ewing sarcoma). Analysis of INI1/BAF-47 expression can offer important clues in the diagnosis of pediatric tumors with rhabdoid phenotype. The integration of clinical, morphologic, immunohistochemical, and genetic data is required to approach a correct diagnosis of pediatric tumor in unusual location with atypical or undifferentiated morphology.
authors.affiliation: Department of Pathology, University of Valencia and University Clinic Hospital, Valencia, Spain.
authors.forename: Isidro
authors.initials: I
authors.lastname: Machado
authors.forename: Rosa
authors.initials: R
authors.lastname: Noguera
authors.forename: Nuria
authors.initials: N
authors.lastname: Santonja
authors.forename: Joaquín
authors.initials: J
authors.lastname: Donat
authors.forename: Rafael
authors.initials: R
authors.lastname: Fernandez-Delgado
authors.forename: Agustín
authors.initials: A
authors.lastname: Acevedo
authors.forename: Marta
authors.initials: M
authors.lastname: Baragaño
authors.forename: Samuel
authors.initials: S
authors.lastname: Navarro
mesh_terms: D000071443:12E7 Antigen; D015703:Antigens, CD; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D015815:Cell Adhesion Molecules; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D002869:Chromosome Aberrations; D004268:DNA-Binding Proteins / Q000378:metabolism; D003937:Diagnosis, Differential; D019008:Drug Resistance, Neoplasm; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D007633:Keratins / Q000378:metabolism; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D000071447:N-Myc Proto-Oncogene Protein; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D009687:Nuclear Proteins / Q000235:genetics; D015513:Oncogene Proteins / Q000235:genetics; D034802:RNA-Binding Protein EWS / Q000235:genetics; D018335:Rhabdoid Tumor / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology / Q000556:secondary; D000071796:SMARCB1 Protein; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology / Q000556:secondary; D014157:Transcription Factors / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D034802:RNA-Binding Protein EWS; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors; D014746:Vimentin; D007633:Keratins