Extraosseous Ewing sarcoma with foci of neuroblastoma-like differentiation associated with EWSR1(Ewing sarcoma breakpoint region 1)/FLI1 translocation without prior chemotherapy.
Peripheral primitive neuroectodermal tumor/Ewing sarcoma and neuroblastoma are distinct malignant tumors belonging to the group of undifferentiated solid pediatric tumors. We report a case of a 14-year-old adolescent girl who presented with a right lower quadrant mass. At surgery, a mobile retroperitoneal mass was entirely removed. Histologic evaluation revealed 2 distinct components; the first, consisting of sheets of undifferentiated cells, was CD99+ and CD56-, whereas the second, consisting of multiple foci of neuropil and maturing neuroblasts, was CD99- and CD56+. Fluorescence in situ hybridization analysis revealed the presence of EWSR1/FLI1 translocation in both histologic distinct components. MYCN (myelocytomatosis viral related oncogene, neuroblastoma derived) was not amplified. The tests for t(11;22) and t(21;22) performed by reverse transcription-polymerase chain reaction were negative. The final diagnosis corresponds to an extraosseous Ewing sarcoma with foci of neuroblastoma-like differentiation. This is the first case, documented by molecular studies, in which neuroblastoma-like differentiation has been noted in primitive neuroectodermal tumor/Ewing sarcoma without prior chemotherapy.
Department of Surgery, Hôpital Sainte-Justine, Montreal, Quebec, Canada.
K
K
Vali
V
V
Kokta
M
M
Beaunoyer
R
R
Fetni
P
P
Teira
Hervé
H
Sartelet
D000293:Adolescent; D002148:Calmodulin-Binding Proteins / Q000235:genetics*; D002454:Cell Differentiation; D005260:Female; D006801:Humans; D009447:Neuroblastoma / Q000473:pathology; D051789:Proto-Oncogene Protein c-fli-1 / Q000235:genetics*; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins / Q000235:genetics*; D012186:Retroperitoneal Neoplasms / Q000235:genetics / Q000473:pathology*; D012512:Sarcoma, Ewing / Q000235:genetics / Q000473:pathology*; D014178:Translocation, Genetic
D002148:Calmodulin-Binding Proteins; C500986:EWSR1 protein, human; C078433:FLI1 protein, human; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins