Sinonasal undifferentiated carcinoma

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Sinonasal undifferentiated carcinoma
Diagnosis in short

SNUC. H&E stain.

LM tumour with variable architecture (nested, trabecular or lobular), small-to-moderate cytoplasm, +/-distinct nucleoli, cell size variable (small to large); glandular and squamous differentiation are absent by definition
LM DDx poorly differentiated squamous cell carcinoma of the head and neck, small cell carcinoma, SMARCB1-deficient sinonasal carcinoma, nasopharyngeal carcinoma, others
IHC pankeratin +ve, EMA +ve, CK7 +ve, CK5/6 -ve, NSE +ve/-ve, chromogranin A -ve, synaptophysin -ve, p63 +ve/-ve
Molecular EBER -ve
Site head and neck

Prevalence rare
Prognosis poor
Clin. DDx other head and neck tumours

Sinonasal undifferentiated carcinoma, abbreviated SNUC, is a rare epithelial malignancy of the head and neck.


  • Aggressive/poor prognosis.
    • In the past, survival was measured in months.[1]
    • With (aggressive) combined modality treatment, the overall five-year survival is approximately 75%.[2]



  • Architecture: nested, trabecular or lobular.
  • Distinct cellular borders.
  • Small-to-moderate cytoplasm.
  • +/-Distinct nucleoli.
  • Tumour cell size variable (small to large).


  • Glandular and squamous differentiation are absent by definition.[4]







Comparison between different sinonasal carcinomas

Based on a modest size study, keratins can useful for subclassifying sinonasal carcinomas:[7]

Diagnosis CK4 CK5/6 CK7 CK13 CK14 CK19
Sinonasal undifferentiated carcinoma (SNUC) +0% +0% +50% +0% +0% +50%
Nasopharyngeal-type undifferentiated carcinoma (NPTC) +0% +80% +0% +80% +0% +100%
Nonkeratinizing squamous cell carcinoma (NKSCC) +0% +90% +0% +80% +80% +90%
Squamous cell carcinoma (keratainizing) +30% +90% +60% +90% +80% +90%


See also


  1. Pitman, KT.; Costantino, PD.; Lassen, LF. (1995). "Sinonasal undifferentiated carcinoma: current trends in treatment.". Skull Base Surg 5 (4): 269-72. PMC 1656535. PMID 17170968.
  2. Al-Mamgani, A.; van Rooij, P.; Mehilal, R.; Tans, L.; Levendag, PC. (Apr 2012). "Combined-modality treatment improved outcome in sinonasal undifferentiated carcinoma: single-institutional experience of 21 patients and review of the literature.". Eur Arch Otorhinolaryngol. doi:10.1007/s00405-012-2008-5. PMID 22476411.
  3. 3.0 3.1 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 38. ISBN 978-0781765275.
  4. 4.0 4.1 Mills, SE. (Mar 2002). "Neuroectodermal neoplasms of the head and neck with emphasis on neuroendocrine carcinomas.". Mod Pathol 15 (3): 264-78. doi:10.1038/modpathol.3880522. PMID 11904342.
  5. Bishop, JA.; Antonescu, CR.; Westra, WH. (Sep 2014). "SMARCB1 (INI-1)-deficient carcinomas of the sinonasal tract.". Am J Surg Pathol 38 (9): 1282-9. doi:10.1097/PAS.0000000000000285. PMID 25007146.
  6. Wadsworth, B.; Bumpous, JM.; Martin, AW.; Nowacki, MR.; Jenson, AB.; Farghaly, H. (Dec 2011). "Expression of p16 in sinonasal undifferentiated carcinoma (SNUC) without associated human papillomavirus (HPV).". Head Neck Pathol 5 (4): 349-54. doi:10.1007/s12105-011-0285-8. PMC 3210220. PMID 21805120.
  7. Franchi A, Moroni M, Massi D, Paglierani M, Santucci M (December 2002). "Sinonasal undifferentiated carcinoma, nasopharyngeal-type undifferentiated carcinoma, and keratinizing and nonkeratinizing squamous cell carcinoma express different cytokeratin patterns". Am J Surg Pathol 26 (12): 1597–604. doi:10.1097/00000478-200212000-00007. PMID 12459626.
  8. Cerilli LA, Holst VA, Brandwein MS, Stoler MH, Mills SE (February 2001). "Sinonasal undifferentiated carcinoma: immunohistochemical profile and lack of EBV association". Am J Surg Pathol 25 (2): 156–63. doi:10.1097/00000478-200102000-00003. PMID 11176064.