title: Biphenotypic sinonasal sarcoma: an expanded immunoprofile including consistent nuclear β-catenin positivity and absence of SOX10 expression.
abstract: Biphenotypic sinonasal sarcoma (BSNS) is a recently recognized low-grade sarcoma that exhibits both neural and myogenic differentiation. This unique dual phenotype stems from recurrent rearrangements in PAX3, a transcription factor that promotes commitment along both lineages. While identification of PAX3 rearrangements by fluorescence in situ hybridization (FISH) can confirm a BSNS diagnosis, this assay is not widely available. This study evaluates whether an expanded immunohistochemical panel can facilitate recognition of BSNS without molecular analysis. Eleven cases of BSNS were identified from the surgical pathology archives of two academic medical centers. In 8 cases, the diagnosis was confirmed by FISH using custom probes for PAX3. In 3 cases, FISH failed but histologic and immunophenotypic findings were diagnostic for BSNS. All 11 BSNS (100%) were at least focally positive for S100 as well as calponin and/or smooth muscle actin. In addition, 10 (91%) of 11 expressed nuclear β-catenin, 8 (80%) of 10 expressed factor XIIIa, 4 (36%) of 11 expressed desmin, and 3 (30%) of 10 expressed myogenin. All 11 tumors were negative for SOX10. While no single marker resolves immunohistochemical overlap between BSNS and its histologic mimickers such as nerve sheath tumors, an extended immunohistochemical panel that includes β-catenin and SOX10 helps to support the diagnosis of BSNS without the need for gene rearrangement studies.
authors.affiliation: Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Rooper
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Shih-Chiang
authors.initials: SC
authors.lastname: Huang
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Cristina R
authors.initials: CR
authors.lastname: Antonescu
authors.affiliation: Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA; Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA; Department of Oncology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Westra
authors.affiliation: Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA; Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA; Department of Oncology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA. Electronic address: jbishop@jhmi.edu.
authors.forename: Justin A
authors.initials: JA
authors.lastname: Bishop
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015142:Baltimore; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D002467:Cell Nucleus / Q000737:chemistry* / Q000276:immunology / Q000473:pathology; D026122:Factor XIIIa / Q000032:analysis; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping / Q000379:methods; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D018008:Myogenin / Q000032:analysis; D009296:Nasal Cavity / Q000737:chemistry* / Q000276:immunology / Q000473:pathology; D060787:Neoplasm Grading; D018193:Neoplasms, Complex and Mixed / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D009519:New York City; D000072041:PAX3 Transcription Factor / Q000235:genetics; D010255:Paranasal Sinus Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D010641:Phenotype; D011237:Predictive Value of Tests; D055757:SOXE Transcription Factors / Q000032:analysis*; D013584:Sarcoma, Synovial / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D051176:beta Catenin / Q000032:analysis*
chemical_list: D014408:Biomarkers, Tumor; C495270:CTNNB1 protein, human; C503799:MYOG protein, human; D018008:Myogenin; D000072041:PAX3 Transcription Factor; C489409:PAX3 protein, human; C527923:SOX10 protein, human; D055757:SOXE Transcription Factors; D051176:beta Catenin; D026122:Factor XIIIa
keywords: Biphenotypic sinonasal sarcoma; Immunohistochemistry; SOX10; Sinonasal tract; β-Catenin