BIPHENOTYPIC SINONASAL SARCOMA OF THE NASOPHARYNX: CASE REPORT

Biphenotypic sinonasal sarcoma is a rare and recently recognized entity. It is a low-grade sarcoma which exhibits both neural and myogenic differentiation. The objective of this study is to report a case of a 25-year-old male patient with nasal congestion and bleeding. Computed tomography showed a tumor mass in the nasopharynx. Microscopic analysis showed a cellular proliferation of spindle cells, forming mainly a herringbone-like fascicular growth pattern. Immunohistochemical analysis showed focal positivity for S100, alpha-smooth muscle actin, and calponin, and negativity for desmin, SOX 10, and FXIIIA. We present an uncommon case of biphenotypic sinonasal sarcoma of the nasopharynx and emphasize the importance of recognizing rare entities with impact on the health of these patients.