Sinonasal teratocarcinosarcoma (SNTCS) is a rare tumor characterized by mixture architecture of epithelial and mesenchymal components. SNTCS is a highly malignant tumor displaying progressive and aggressive growth with poor prognosis. Only about 40% of all patients survive after five years. It seems the combination of surgery and radiotherapy currently is the most
effective treatment. In this report we are presenting a 24-year-old Iranian male with SNTCS of right nasal cavity and paranasal sinuses who was referred to our radiotherapeutic Oncology
department, Tehran cancer institute, for post operative radiation treatment. The patient is treated with combination of surgical excision, postoperative radiation therapy and then followed for 10 months. The clinical and pathologic features, as well as its clinical course are presented. SNTSC is a rare condition and rapid progressive tumor. So far, the most widely accepted therapeutic plan for its treatment has been surgical excision with postoperative radiation therapy. Iran . J. Radiat. Res., 2004; 2 (3): 159-162