Teratocarcinosarcoma (TCS) is a very rare and aggressive neoplasm characterized by teratoma and carcinosarcoma components. The authors report on a case of TCS in the oral cavity of a child. Rapid growth and extensive local destruction were prominent features prior to treatment. Histologic examination revealed various tissue elements, such as epithelial, mesenchymal, and neuroectodermal components. Chemotherapy was effective in reducing tumor mass, followed by partial anterior mandibulectomy and reconstruction with composite microvascular tissue transfer. The approach allowed radical resection of the tumor and functional reconstruction with excellent aesthetic results. (c) 2004 Wiley-Liss, Inc.