Sinonasal undifferentiated carcinoma: morphological heterogeneity, diagnosis, management and biological markers.

Sinonasal undifferentiated carcinoma is a highly aggressive lesion arising in the superior nasal cavity and paranasal sinuses. Differential diagnosis is wide because a range of similar lesions can present at this site. There is increasing evidence that sinonasal undifferentiated carcinoma is a surface (Schneiderian) epithelial-derived malignancy, with or without concurrent neuroendocrine differentiation. Prognosis is poor; recurrence with metastasis to lymph nodes and distant sites is frequent. A combination of radical surgery, chemotherapy and radiotherapy appears to provide the best chance of survival.