title: Maturation toward neuronal tissue in a Ewing sarcoma of bone after chemotherapy.
abstract: BACKGROUND
  Ewing sarcoma is the second most common bone tumor, occurring mainly in children and young adults. It shows a typical primitive, small round cell morphology and a characteristic fusion oncogene involving EWSR1 and members of the ETS family in most of the cases. Neuronal maturation after chemotherapy is a rare phenomenon and we herein describe such an exceptional case.
  
  
  METHODS
  An 8-year old boy was diagnosed with a Ewing sarcoma in the left femur. On biopsy the morphology was typical and there was an EWSR1-FLI1 gene fusion. He underwent neo-adjuvant chemotherapy and resection of the tumor. On microscopic evaluation, part of the tumor showed ganglioneuroblastoma-like differentiation with expression of neuronal markers. The continued presence of EWSR1 rearrangement in both the blue round cell component and the ganglioneuroblastoma-like component was shown by FISH analysis.
  
  
  CONCLUSIONS
  In conclusion, this case describes the possibility of a Ewing sarcoma to differentiate into a ganglioneuroblastoma-like lesion after neo-adjuvant chemotherapy treatment; the prognostic value of this phenomenon remains questionable.
authors: Department of Pathology, Radboud University Medical Center, P.O. Box 9101, Nijmegen, 6500 HB, The Netherlands. Myrthe.Salet@radboudumc.nl.
authors: Maria Carolina Wilhelmina
authors: MC
authors: Salet
authors: Department of Pathology, Radboud University Medical Center, P.O. Box 9101, Nijmegen, 6500 HB, The Netherlands.
authors: Rob
authors: R
authors: Vogels
authors: Department of Pediatric Oncology, Radboud University center, P.O. Box 9101, Nijmegen, 6500 HB, The Netherlands.
authors: Paul
authors: P
authors: Brons
authors: Department of Orthopedics, Radboud University Center, P.O. Box 9101, Nijmegen, 6500 HB, The Netherlands.
authors: Bart
authors: B
authors: Schreuder
authors: Department of Pathology, Radboud University Medical Center, P.O. Box 9101, Nijmegen, 6500 HB, The Netherlands.
authors: Uta
authors: U
authors: Flucke
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002148:Calmodulin-Binding Proteins / Q000235:genetics*; D002454:Cell Differentiation; D017024:Chemotherapy, Adjuvant; D002648:Child; D004317:Doxorubicin / Q000008:administration & dosage; D005047:Etoposide / Q000008:administration & dosage; D005266:Femoral Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000235:genetics* / Q000601:surgery; D005269:Femur / Q000473:pathology; D018305:Ganglioneuroblastoma / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000235:genetics*; D015321:Gene Rearrangement; D006801:Humans; D007069:Ifosfamide / Q000008:administration & dosage; D008297:Male; D020360:Neoadjuvant Therapy; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D011379:Prognosis; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins / Q000235:genetics*; D012512:Sarcoma, Ewing / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000235:genetics* / Q000601:surgery; D016896:Treatment Outcome; D014750:Vincristine / Q000008:administration & dosage
chemical_list: D002148:Calmodulin-Binding Proteins; C500986:EWSR1 protein, human; C576197:EWSR1-FLI1 fusion protein, human; D015514:Oncogene Proteins, Fusion; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins; D014750:Vincristine; D005047:Etoposide; D004317:Doxorubicin; D007069:Ifosfamide
keywords: Differentiation; Ewing sarcoma; Maturation; Neural; Pathology