Benign lipoblastoma: report of a case.

Light and electron microscopic studies of a benign, well circumscribed lipoblastoma in a 10-year-old boy were performed. Ultrastructural examination demonstrated lipocytes, lipoblasts, undifferentiated mesenchymal cells, and occasional hibernoma cell types. Myxoid liposarcoma as a differential diagnosis was considered. However, an absence of mitosis and the hyperchromatic and bizarre nuclei of the lipoblasts ruled out the possiblity of malignancy.