Biphenotypic Sinonasal Sarcoma: A Series of Six Cases with Evaluation of the Clinicopathological Characteristics and Prognosis

Materials and Methods: Six cases, previously diagnosed as BSS during 2005 to 2017, were selected and retrieved from our archives, two of them were previously diagnosed as sarcomas of low histological grade of malignancy. The medical record and imaging data were collected, besides the histological slides (hematoxylin and eosin staining). Using antibodies directed against the following antigens: Protein S-100, Caldesmon, Smooth muscle actin, MyoD1, Myogenin, CD34 and Cytokeratins AE1/AE3. The immunohistochemical staining was classified as “negative,”“focal positive,” or “diffuse positive.”Results: The six cases had an age range between 29 and 60 years, with female preference (83.4%). The localization os de tumors was in the nasal cavity in 4 cases (66, 7%), temporal bone in 1 case (16.4%) and hard palate/maxillary sinus in 1 case (16.4%). Four cases presented partial nasal obstruction, epistaxis …