WT1 staining reliably differentiates desmoplastic small round cell tumor from Ewing sarcoma/primitive neuroectodermal tumor. An immunohistochemical and molecular diagnostic study.
Differentiating desmoplastic small round cell tumor (DSRCT) from another similar small round cell tumor of childhood, the Ewing sarcoma/primitive neuroectodermal tumor (EWS/PNET), can be difficult because morphologic and immunohistochemical features overlap. We studied the predictive value of immunohistochemistry with an antibody to the C-terminal region of the Wilms tumor (WT1) protein for differentiating DSRCT from EWS/PNET in 24 malignant small round cell tumors that had been previously diagnosed as DSRCT or EWS/PNET by standard methods. We performed reverse transcriptase-polymerase chain reaction (RT-PCR) analysis in cases with available tissue as a confirmatory measure: 6 of 13 DSRCTs were informative by RT-PCR, and 6 of 6 showed an EWS-WT1 fusion; all 13 DSRCTs showed strong, definitive nuclear staining with the WT1 antibody. All 11 EWS/PNETs were WT1 antibody negative; 7 of 11 cases classified as EWS/PNET were informative by RT-PCR, and 7 of 7 showed an EWS-FLI-1 fusion. For cases in which the morphologic and immunohistochemical features are consistent with a diagnosis of DSRCT, WT1 antibody staining predicts the EWS-WT1 translocation with high sensitivity and specificity and is, therefore, useful for differentiating DSRCT from EWS/PNET when genetic information is unavailable.
Hill
D A
DA
Laboratory of Surgical Pathology, Washington University Medical Center, St Louis, MO, USA.
Pfeifer
J D
JD
Marley
E F
EF
Dehner
L P
LP
Humphrey
P A
PA
Zhu
X
X
Swanson
P E
PE
D000008:Abdominal Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism; D015139:Blotting, Southern; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers / Q000737:chemistry; D004273:DNA, Neoplasm / Q000032:analysis; D004268:DNA-Binding Proteins / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D018222:Desmoid Tumors / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D018242:Neuroectodermal Tumors, Primitive / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000378:metabolism; D010307:Parotid Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012512:Sarcoma, Ewing / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000378:metabolism; D025721:WT1 Proteins
D014408:Biomarkers, Tumor; D017931:DNA Primers; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D015514:Oncogene Proteins, Fusion; D014157:Transcription Factors; D025721:WT1 Proteins