Unusual myogenic and melanocytic differentiation of soft tissue pPNETs: an immunohistochemical and molecular study of 3 cases.
All of the members of the peripheral primitive neuroectodermal tumor family (Ewing sarcomas, neuroectodermal tumors of bone, peripheral neuroepitheliomas, and Askin tumors) have similar morphologic and immunophenotypical features (ie, the proliferation of small and medium-sized round cells in a fibrous background showing strong and diffuse immunohistochemical positivity for CD99), and the common cytogenetic abnormality of a nonrandom translocation involving the EWS gene and one of several members of the erythroblastosis virus transforming sequence family of transcription factors. The combination of clinical information and morphologic/immunophenotypical characteristics is usually sufficient for a correct diagnosis, but there are rare cases in which an unusual predominant or multidirectional immunophenotypical differentiation makes diagnosis a challenge and requires the use of molecular cytogenetic or molecular techniques. We describe 3 such cases in which we employed fluorescence in-situ hybridization analysis to detect translocation involving the EWS gene and reverse transcription polymerase chain reaction followed by sequencing to detect the fusion transcript EWS-FLI1.
Barisella
Marta
M
Anatomic Pathology B Unit, Department of Pathology, IRCCS Istituto Nazionale Tumori of Milan, Milan, Italy. marta.barisella@istitutotumori.mi.it
Collini
Paola
P
Orsenigo
Marta
M
Aiello
Antonella
A
Paties
Carlo Terenzio
CT
Dileo
Palma
P
Pilotti
Silvana
S
D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D004273:DNA, Neoplasm / Q000032:analysis; D003893:Desmin / Q000032:analysis; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008544:Melanocytes / Q000737:chemistry / Q000473:pathology*; D032342:Muscle Cells / Q000737:chemistry / Q000473:pathology*; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000235:genetics / Q000473:pathology*; D015514:Oncogene Proteins, Fusion / Q000032:analysis / Q000235:genetics; D051789:Proto-Oncogene Protein c-fli-1 / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D034802:RNA-Binding Protein EWS / Q000032:analysis / Q000235:genetics; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D014178:Translocation, Genetic
D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D003893:Desmin; C106031:EWS-FLI fusion protein; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D012333:RNA, Messenger; D034802:RNA-Binding Protein EWS