Lipoblastoma is a rare type of benign tumor occurring in infants. We report a case of mesenteric lipoblastoma with histologic, electron microscopic and cytogenetic studies. The microscopic features of this tumor including lipoblastic proliferation and prominent immature capillary beds were typical of lipoblastoma. Cytogenetic study showed a karyotype 46,XX, inv (8) (p 21.1; q 24.2). We discuss the usefulness of cytogenetic study associated to fluorescent in situ hybridization, in the diagnosis of the lipoblastic tumors, i.e. myoxoid liposarcoma and lipoblastoma.