Sinonasal carcinoma

The various types of carcinoma which may involve the nasal sinuses need to be distinguished:

• Squamous cell carcinoma, SCC.

• Nonkeratinising squamous cell carcinoma, NKSCC, cylindrical cell carcinoma, transitional-type carcinoma. They are negative for EBER-11.

• Nasopharyngeal-type undifferentiated carcinoma, NPTC, arising in the nasal cavity or paranasal sinuses, or extending from the nasopharynx.

• sinonasal undifferentiated carcinoma, SNUC: the main differential diagnosis is NPTC.

Aetiology

• NPTC: Very common in the far east. EBV is strongly associated; tumours are positive for EBER-11.

• SNUC: smoking, previous retinoblastoma, therapeutic irradiation have all been implicated. EBV probably does NOT have a role, either in the USA or in Taiwan1.

Histopathology

• SCC: easily recognised if well differentiated and keratinising but problematic if poorly differentiated. Poorly differentiated SCC consists of solid masses of pleomorphic polygonal cells with variable amounts of eosinophilic cytoplasm and large nuclei with prominent nucleoli. Focal keratinisation and intercellular bridges can be found. There may be dysplasia or the overlying epithelium. There is commonly an infiltrate of granulocytes and lymphocytes.

• NKSCC: ribbons of cylindrical cells normal to the length of the ribbons. There may be comedo necrosis. There may be dysplasia of the overlying epithelium.

• NPTC: irregular syncytial sheets of cells with indistinct margins, markedly vesicular nuclei and prominent nucleoli. There may be spindle cell areas. There is usually an infiltrate of plasma cells and lymphocytes, creating a lymphoepithelioma picture. Necrosis is uncommon.

• SNUC: sheets, nests, trabeculae or ribbons of small to medium size cells. Cytoplasm is relatively scanty and nuclei large. Nucleoli are often prominent. The mitotic rate is high. There is frequently necrosis and vascular invasion. Homer Wright rosettes, squamous or glandular differentiatin are not seen3.

Immunohistochemistry

SCC and NKSCC show similar cytokeratin profiles, with immunoreactivity for CK4 and CK7 favouring SCC. NPTC is distinguished from SCC and NKSCC by its negativity for CK14.

SNUC has a different cytokeratin profile from the other carcinomas, expressing only simple cytokeratins (CK7, CK8 and CK19).

Prognosis

• NKSCC: prognosis is relatively good1.

• SNUC: a very aggressive tumour, with most patients dying within one year1.

Differential diagnosis.

• SNUC (epithelial differentiation is often rudimentary):

• • melanoma
    

  • non-Hodgkin's lymphoma
    

  • embryonal rhabdomyosarcoma
    

  • olfactory neuroblastoma
    

  • nasopharyngeal carcinoma
    

  • small cell carcinoma

Prognosis

• SNUC: dismal

References

1Jeng, Y. M., Sung, M. T., Fang, C. L. Sinonasal undifferentiated carcinoma and nasopharyngeal-type undifferentiated carcinoma: two clinically, biologically, and histopathologically distinct entities. Am J Surg Pathol 2002;26:371-376.

2Franchi, A., Moroni, M., Massi, D., Paglierani, M. and Santucci, M. Sinonasal undifferentiated carcinoma, nasopharyngeal-type undifferentiated carcinoma, and keratinizing and nonkeratinizing squamous cell carcinoma express different cytokeratin patterns. Am J Surg Pathol 2002;26:1597-604.

3Perez-Ordonex B. Special tumours of the head and neck. Current Diagnostic Pathology 2003;9:366-383.

This page last revised 10.2.2004

©SMUHT/PW Bishop