title: Evidence of neural differentiation in a case of post-therapy primitive neuroectodermal tumor/Ewing sarcoma of bone.
abstract: Neural differentiation with the appearance of ganglion-like cells has been reported in untreated primitive neuroectodermal tumor/Ewing sarcoma (PNET/EWS) at peculiar sites, such as the cauda equina, and following treatment. The case is presented here of a 17-year-old girl with a tumor in the iliac bone. An open biopsy was diagnosed as PNET/EWS of the bone. The tumor had the typical morphology of this tumor type and showed diffuse membranous immunoreactivity for CD99, intense immunoreactivity for synaptophysin, and focal immunoreactivity for neuron-specific enolase and S-100 protein. Occasional reactivity for vimentin was evident, while no immunoreactivity for NB84a, Hu, chromogranins A and B, neurofilaments, cytokeratins, and desmin was present. The patient underwent chemotherapy and radiotherapy, followed by right internal hemipelvectomy. The post-treatment residual viable tumor showed a morphologic appearance resembling a neuroblastoma, with immunoreactivity for NB84a, Hu, synaptophysin, and chromogranins A and B, but not for CD99. RT-PCR performed on tumor tissue before and after therapy showed the presence of the EWS-FLI1 fusion transcript, type I in both samples. This case of PNET/EWS is unique in the sense of showing the typical fusion transcript associated with this tumor both in the morphologically typical pretherapy tumor and in the sample from the post-therapy specimen showing neuroblastoma-like features.
authors.affiliation: Department of pathology, Experimental Oncology, Istituto Nazionale Tumori, Milan, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Collini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Mezzelani
authors.forename: Piergiorgio
authors.initials: P
authors.lastname: Modena
authors.forename: Paolo
authors.initials: P
authors.lastname: Dagrada
authors.forename: Elena
authors.initials: E
authors.lastname: Tamborini
authors.forename: Roberto
authors.initials: R
authors.lastname: Luksch
authors.forename: Alessandro
authors.initials: A
authors.lastname: Gronchi
authors.forename: Pierina
authors.initials: P
authors.lastname: Navarria
authors.forename: Gabriella
authors.initials: G
authors.lastname: Sozzi
authors.forename: Silvana
authors.initials: S
authors.lastname: Pilotti
mesh_terms: D000293:Adolescent; D014408:Biomarkers, Tumor; D001859:Bone Neoplasms / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D002471:Cell Transformation, Neoplastic; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging / Q000473:pathology; D016609:Neoplasms, Second Primary; D009447:Neuroblastoma / Q000235:genetics / Q000473:pathology / Q000628:therapy; D018242:Neuroectodermal Tumors, Primitive / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism; D051789:Proto-Oncogene Protein c-fli-1; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D034802:RNA-Binding Protein EWS; D011859:Radiography; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012512:Sarcoma, Ewing / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; C106031:EWS-FLI fusion protein; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D034802:RNA-Binding Protein EWS; D014157:Transcription Factors