title: Role of p40 and cytokeratin 5/6 in the differential diagnosis of sinonasal undifferentiated carcinoma.
abstract: Sinonasal undifferentiated carcinoma (SNUC) is an epithelial neoplasm of sinonasal region which does not exhibit a squamous or glandular differentiation. The challenge in diagnosis of this entity is the rarity of the disease, the varying morphology of the tumor which leads to gamut of differential diagnosis and the paucity of consistent immunohistochemical markers except pancytokeratin. Forty-one cases of sinonasal epithelial neoplasm consisting of 11 cases of SNUC and 10 cases each of high-grade (grade 3 and 4) esthesioneuroblastoma, undifferentiated nasopharyngeal carcinoma, and poorly differentiated squamous cell carcinoma of the sinonasal region were analyzed for morphology and immunoexpression of CK5/6 and p40. It was found that SNUC did not exhibit immunohistochemical expression of p40 and CK 5/6, suggesting that these could be useful negative immune markers for diagnosis of SNUC.
authors.affiliation: Department of Pathology, All India Institute of Medical Sciences, New Delhi, India. Electronic address: singhlavleen04@yahoo.co.in.
authors.forename: Lavleen
authors.initials: L
authors.lastname: Singh
authors.affiliation: Department of Pathology, All India Institute of Medical Sciences, New Delhi, India. Electronic address: rrriiicha@yahoo.co.in.
authors.forename: Richa
authors.initials: R
authors.lastname: Ranjan
authors.affiliation: Department of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Sudheer
authors.initials: S
authors.lastname: Arava
authors.affiliation: Department of Pathology, All India Institute of Medical Sciences, New Delhi, India. Electronic address: makusi@gmail.com.
authors.forename: M K
authors.initials: MK
authors.lastname: Singh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D002277:Carcinoma / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053555:Keratin-5 / Q000032:analysis*; D053553:Keratin-6 / Q000032:analysis*; D008297:Male; D008444:Maxillary Sinus Neoplasms / Q000175:diagnosis*; D008875:Middle Aged; D010255:Paranasal Sinus Neoplasms / Q000175:diagnosis; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D053555:Keratin-5; D053553:Keratin-6
keywords: CK5/6; Epithelial sinonasal malignancies; SNUC; p40