title: Peripheral primitive neuroectodermal tumor with postchemotherapy neuroblastoma-like differentiation.
abstract: We report the case of an 11-year-old girl with a retroperitoneal tumor in the left upper quadrant. The girl was admitted to hospital with weight loss and a painless abdominal mass that on biopsy was diagnosed as a peripheral primitive neuroectodermal tumor/Ewing sarcoma (pPNET/EWS) of the soft tissue. The patient underwent chemotherapy followed by surgical resection of the tumor 5 months after diagnosis. The posttreatment residual viable tumor showed a morphologic appearance resembling a neuroblastoma. Interphase and metaphase fluorescent in situ hybridization (FISH) studies performed on the pretreatment and posttreatment samples showed the presence of a t(11;22) rearrangement resulting in EWSR1/FLI1 gene fusion consistent with pPNET/EWS in both specimens. This case is unusual in the sense of showing the typical gene fusion for pPNET/EWS both in the pretherapy sample with the typical morphological appearance of this tumor and in the posttherapy specimen showing neural differentiation suggestive of a neuroblastoma.
authors.affiliation: Birmingham Children's Hospital, Department of Histopathology, West Midlands, UK. aweissferdt@doctors.org.uk
authors.forename: Annikka
authors.initials: A
authors.lastname: Weissferdt
authors.forename: Kim
authors.initials: K
authors.lastname: Neuling
authors.forename: Martin
authors.initials: M
authors.lastname: English
authors.forename: Suren
authors.initials: S
authors.lastname: Arul
authors.forename: Dominic
authors.initials: D
authors.lastname: McMullan
authors.forename: Alison
authors.initials: A
authors.lastname: Ely
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Bründler
authors.forename: Rachel
authors.initials: R
authors.lastname: Brown
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002454:Cell Differentiation; D002648:Child; D002880:Chromosomes, Human, Pair 11; D002892:Chromosomes, Human, Pair 22; D003520:Cyclophosphamide / Q000627:therapeutic use; D003609:Dactinomycin / Q000627:therapeutic use; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D009447:Neuroblastoma / Q000503:physiopathology*; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology* / Q000532:radiotherapy / Q000601:surgery; D050596:Oncogene Fusion; D018714:Radiotherapy, Adjuvant; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014178:Translocation, Genetic; D014750:Vincristine / Q000627:therapeutic use
chemical_list: D003609:Dactinomycin; D014750:Vincristine; D003520:Cyclophosphamide