[Sinonasal undifferentiated carcinoma. A rare and aggressive neoplasm of the nasal cavity and paranasal sinuses].

Sinonasal undifferentiated carcinoma (SNUC) is a rare tumor of the nasal cavity and paranasal sinuses first described in 1986. Olfactory neuroblastoma and SNUC may appear quite similar on histological examination. Due to the fact that olfactory neuroblastoma has a much better prognosis, a distinction with SNUC has to be drawn. We report a case of SNUC and describe the role of immunohistochemistry in making an accurate histological diagnosis. In addition, potential factors influencing the development of SNUC described in the literature and current treatment modalities are discussed. Despite aggressive and multimodal treatment regimens, the outcomes of patients suffering from SNUC have remained dismal. A randomized controlled clinical study could be the basis for determining the optimal treatment for SNUC.