Sinonasal Undifferentiated Carcinoma (SNUC)

63-year-old female with a longstanding history of anosmia and nasal obstruction. There is a T1-hypointense, T2/FLAIR-isointense, enhancing nasal cavity mass. The lesion restricts diffusion. The mass extends into the anterior cranial fossa, including involvement of the olfactory fossa. A differential of esthesioneuroblastoma, squamous cell carcinoma, and sinonasal undifferentiated carcinoma was given. There are T1-hyperintensities in the bilateral maxillary antra and ethmoid air cells compatible with retained secretions and debris secondary to obstruction of the sinus outflow tracts. On biopsy, this mass was a sinonasal undifferentiated carcinoma or SNUC. SNUC is a rare and highly aggressive neoplasm of the paranasal sinuses. Tumors tend to be large and advanced at initial presentation. Prognosis is poor, with treatment typically entailing wide excision followed by radiation and chemotherapy.