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biphenotypic sinonasal sarcoma

Friday 4 November 2016

BSNS; LGSSNMF; biphenotypic sinonasal sarcoma With focal rhabdomyoblastic differentiation. low-grade sinonasal sarcoma with neural and myogenic features

Definition: 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.

A PAX3-NCOA1 fusion in BSNS, associated with focal rhabdomyoblastic differentiation. It 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.

Molecular biology

- NCOAX1-PAX3 fusion gene
- MAML3-PAX3 fusion gene

Open references

- Newly Described Tumor Entities in Sinonasal Tract Pathology.
Bishop JA.
Head Neck Pathol. 2016 Mar;10(1):23-31. doi : 10.1007/s12105-016-0688-7. Epub 2016 Feb 1. Review
PMID: 26830406 Free


- Novel PAX3-NCOA1 Fusions in Biphenotypic Sinonasal Sarcoma With Focal Rhabdomyoblastic Differentiation. Huang SC, Ghossein RA, Bishop JA, Zhang L, Chen TC, Huang HY, Antonescu CR. Am J Surg Pathol. 2016 Jan;40(1):51-9. doi : 10.1097/PAS.0000000000000492 PMID: 26371783