We report a case of hemangiopericytoma arising from the tongue of a 12-year-old child. Ultrastructurally, tumor cells revealed discontinuous basal lamina, intermediate-type intercellular junctions, subplasmalemmal thickenings, and smooth muscle-type cytoplasmic filaments. In addition, occasional oligocilia and test tube-like inclusions were observed. Karyotypic analysis of the tumor cells revealed two balanced translocations that have not been reported previously in pediatric solid tumors: one involved chromosomes 1 and 3, t(1;3)(p22;q21), and the other involved chromosomes 7 and 12, t(7;12)(p22;q13). This is the first report of cytogenetic aberrations in a pediatric hemangiopericytoma. Correlation with genetic findings in adult hemangiopericytomas suggests that the chromosome 12q13 rearrangement might be of particular importance.