Biphenotypic sinonasal sarcoma – Description of radiologic, intraoperative and pathologic findings

Abstract

Biphenotypic sinonasal sarcomas were initially described in 2012 and introduced to the 4th edition of the World Health Organization (WHO) classification of head and neck tumors as a new disease entity. We present the first comprehensive case description combining radiologic, surgical and pathologic findings of a biphenotypic sinonasal sarcoma in a young patient who presented with nonspecific sinonasal obstructive symptoms, left orbital pain and proptosis. While there is no distinct radiologic imaging finding to differentiate biphenotypic sinonasal sarcomas from other sinonasal malignancies, immunohistochemistry and histopathology were able to show the characteristic combination of neural and myogenic differentiation of the tumor. Overall, the tumor is considered rare and slow growing with locally aggressive features but no tendency to metastasize. Biphenotypic sinonasal sarcomas are primarily treated with surgical resection. Postoperative radiation treatment is recommended with but not limited to positive or close surgical margins, high-grade pathologic tumor classification or imaging evidence of perineural spread. Primary radiation therapy, possibly combined with chemotherapy, is reserved for palliative treatment approaches or patients who refuse surgery. Keywords: Ethmoid sinus, Malignancy, Nasal cavity, Sinonasal sarcoma, Sinus