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Diagnostic utility of EWS break‐apart fluorescence in situ hybridization in distinguishing between non‐cutaneous melanoma and clear cell sarcoma
Author(s) -
Song Joon Seon,
Choi Jene,
Kim Ji Hun,
Jang Se Jin,
Cho KyungJa
Publication year - 2010
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1111/j.1440-1827.2010.02570.x
Subject(s) - fluorescence in situ hybridization , sarcoma , clear cell sarcoma , melanoma , pathology , chromosomal translocation , fusion gene , in situ hybridization , biology , immunohistochemistry , gene rearrangement , gene duplication , fish <actinopterygii> , exon , tissue microarray , soft tissue , gene , medicine , gene expression , cancer research , genetics , chromosome , fishery
Clear cell sarcoma (CCS) is a rare soft tissue sarcoma with morphological similarities to malignant melanoma (MM), but with a distinct genetic background that includes the chromosomal translocation t(12;22)(q13;q12). Clear cell sarcoma is often misdiagnosed as MM because of similarities in target locations and immunophenotypes. Eighteen cases with MM in non‐cutaneous sites were subjected to fluorescence in situ hybridization (FISH) to assess EWS gene breakage. Tissue microarrays were constructed using formalin‐fixed, paraffin‐embedded tissue and the EWSR1 (22q12) dual‐color, break‐apart rearrangement probe (Vysis) was used. Two patients were classified as CCS with EWS gene rearrangement, with a mean of 67.5% positive cells per sample according to break‐apart FISH. The remaining 16 patients lacked break‐apart signals of the EWS gene. The presence of type 1 (EWS exon 8‐ATF1 exon 4) fusion transcripts was confirmed in FISH‐positive patients by RT‐PCR. Retrospective analysis revealed that the masses were located in the foot and buttock, respectively. Morphologically, tumor cells were not typical for those of CCS or MM. Break‐apart FISH is an accurate and convenient method for differentiating between MM and CCS. Molecular detection of EWS gene rearrangement, either by break‐apart FISH or RT‐PCR, is mandatory in subjects with melanotic tumors of soft tissue.