Sinonasal desmoplastic small round cell tumor.

Desmoplastic small round cell tumor (DSRCT) is a rare malignancy with poor prognosis that generally involves the peritoneum. Only rare cases occur outside the abdomen. Its diagnosis can be achieved only by immunohistochemistry and cytogenetic studies. We describe a case of a 61-year-old man referred to our department with a primary sinonasal tumor. The DSRCT diagnosis was confirmed by the presence of a polyphenotypic immunoprofile (positive for cytokeratin, desmin, and neuronspecific enolase) and the characteristic EWS-WT1 gene fusion resulting from the t(11;22)(p13;q12) reciprocal translocation. This reported case of DSRCT draws attention to the importance of including DSRCT in the differential diagnosis of sinonasal tumors.