title: Clear cell sarcoma of soft tissue: diagnostic utility of fluorescence in situ hybridization and reverse transcriptase polymerase chain reaction.
abstract: A 7-year-old girl presented with pain and progressive swelling on the left plantar surface. Biopsy of a 2.5 cm mass showed nests of large round to oval neoplastic cells with abundant amphophilic to clear cytoplasm, prominent nucleoli and high mitotic activity. Occasional cells showed spindled morphology. Infrequent melanin pigment was present. Melanocytic markers (HMB45, S-100) were diffusely positive. A diagnosis of clear cell sarcoma of soft tissue (CCSS) was made, and the mass was re-excised with negative margins. 28 months later, a 1.0 cm pulmonary nodule was identified and wedge excision showed metastatic CCSS. Cytogenetics showed a complex karyotype (unbalanced translocation der(12;14)(q10;q10), additional chromosome 22 material of unknown origin). Although the CCSS translocation t(12;22)(q13;q12) was not identified, EWSR1 gene rearrangement was detected by fluorescence in situ hybridization (FISH). Reverse transcription polymerase chain reaction (RT-PCR) showed an EWS-ATF1 fusion transcript, confirmed by direct sequencing. CCSS requires differentiation from malignant melanoma, because of overlapping clinical presentations, sites of involvement, histomorphology, immunocytochemical profiles and ultrastructure. In many circumstances, definitive diagnosis is only possible with confirmation of the CCSS-defining translocation.
authors.affiliation: Department of Pathology, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Choladda V
authors.initials: CV
authors.lastname: Curry
authors.forename: Megan K
authors.initials: MK
authors.lastname: Dishop
authors.forename: M John
authors.initials: MJ
authors.lastname: Hicks
authors.forename: Rizwan
authors.initials: R
authors.lastname: Naeem
authors.forename: Jon A
authors.initials: JA
authors.lastname: Reed
authors.forename: Dolores H
authors.initials: DH
authors.lastname: López-Terrada
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D002148:Calmodulin-Binding Proteins / Q000235:genetics; D002648:Child; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018227:Sarcoma, Clear Cell / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000601:surgery; D014157:Transcription Factors / Q000235:genetics*; D014178:Translocation, Genetic; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D002148:Calmodulin-Binding Proteins; C111598:EWS-ATF1 fusion protein, human; C500986:EWSR1 protein, human; D015514:Oncogene Proteins, Fusion; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins; D014157:Transcription Factors