Ameloblastic carcinoma is an ameloblastoma wi th histological malignant transformation with 01' without metastatic di sease_ We report an ameloblastic carcinoma ex ameloblastoma of right mandibular body in 7 -year-old girl with a heterogeneo us hi stologic components_ The tumor s howed so lid s heets composed of atypical kerati nized squamous cells. small ovoid cell s. and s pind le cells in addi tion to a bit of beni gn ameloblastoma component_ Immunohis tochemically, the squ amous cells were strongly cytokemtin posi ti ve/vimentin negati ve and the small ovoid and spindle ce lls were weakJy cytokeratin positi ve/v imentin pos it ive_