Novel PAX3-NCOA1 fusions in biphenotypic sinonasal sarcoma with focal rhabdomyoblastic differentiation Journal Article
| Authors: | Huang, S. C.; Ghossein, R. A.; Bishop, J. A.; Zhang, L.; Chen, T. C.; Huang, H. Y.; Antonescu, C. R. |
| Article Title: | Novel PAX3-NCOA1 fusions in biphenotypic sinonasal sarcoma with focal rhabdomyoblastic differentiation |
| Abstract: | Sarcomas arising in the sinonasal region are uncommon and encompass a wide variety of tumor types, including the newly described biphenotypic sinonasal sarcoma (BSNS), which is characterized by a monomorphic spindle cell proliferation with dual neural and myogenic phenotypes. Most BSNSs harbor a pathognomonic PAX3-MAML3 fusion driven by t(2;4)(q35;q31.1), whereas the alternative fusion partner gene remains unidentified in a subset of PAX3-rearranged cases. As NCOA1 on 2p23 is a known partner in PAX3-related fusions in other tumor types (ie, alveolar rhabdomyosarcoma), we investigated its status by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction assays in 2 BSNS cases showing only PAX3 gene rearrangements. Novel PAX3-NCOA1 fusions were identified in these 2 index cases showing an inv(2)(q35p23) by FISH and confirmed by reverse transcription polymerase chain reaction. Five additional BSNS cases with typical morphology were studied by FISH, revealing a PAX3-MAML3 fusion in 4 cases and only PAX3 rearrangement in the remaining case without abnormalities in MAML3 or NCOA1 gene. Except for 1 case with surface ulceration, all other tumors lacked increased mitotic activity or necrosis, and all cases immunohistochemically coexpressed S100 protein and actin, but lacked SOX10 reactivity. Interestingly, the 2 PAX3-NCOA1-positive cases showed desmin reactivity and displayed a small component of rhabdomyoblastic cells, which were not seen in the more common PAX3-MAML3 fusion cases. In conclusion, we report a novel PAX3-NCOA1 fusion in BSNS, which appears to be associated with focal rhabdomyoblastic differentiation and should be distinguished from PAX3-NCOA1-positive alveolar rhabdomyosarcoma or malignant Triton tumor. SOX10 immunohistochemistry is a useful marker in distinguishing BSNS from peripheral nerve sheath tumors. © 2015 Wolters Kluwer Health, Inc. |
| Keywords: | pax3; biphenotypic sinonasal sarcoma; low-grade sinonasal sarcoma with neural and myogenic features; maml3; ncoa1 |
| Journal Title: | American Journal of Surgical Pathology |
| Volume: | 40 |
| Issue: | 1 |
| ISSN: | 0147-5185 |
| Publisher: | Lippincott Williams & Wilkins |
| Date Published: | 2016-01-01 |
| Start Page: | 51 |
| End Page: | 59 |
| Language: | English |
| DOI: | 10.1097/pas.0000000000000492 |
| PROVIDER: | scopus |
| PUBMED: | 26371783 |
| PMCID: | PMC4679641 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 3 February 2016 -- Source: Scopus |
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