Lipoblastoma and liposarcoma in children: an analysis of 9 cases and a review of the literature.

OBJECTIVES To review the experience at a children's hospital of lipoblastoma and liposarcoma and to identify any factors that would differentiate one type of tumour from the other. DESIGN A retrospective case series. SETTING British Columbia's Children's Hospital a tertiary-care pediatric centre. PATIENTS All patients with a pathological diagnosis of lipoblastoma and liposarcoma recorded over 12 years. MAIN OUTCOME MEASURES The frequency of lipoblastoma and liposarcoma, identified from biopsy specimens of pediatric adipose tumours. The clinical, pathological and cytogenetic variables between lipoblastoma and liposarcoma. RESULTS One hundred and forty-nine adipose tumours were recorded. Seven (4.7%) were lipoblastomas and 2 (1.3%) were liposarcomas. All tumours presented as asymptomatic, slow-growing, soft-tissue masses. The children with lipoblastoma tended to be younger, but 29% were over 3 years of age. The liposarcoma patients were aged 9 and 14 years. One liposarcoma was of myxoid type and the other was a round cell variant. Karyotypes were reported for 1 lipoblastoma and 1 liposarcoma. The myxoid liposarcoma karyotype was 46,XY,t(12;16)(q13;p11), and the lipoblastoma was reported as 46,XY,der(8)?t(8q;?),+mar. CONCLUSIONS Lipoblastoma is an unusual childhood neoplasm and liposarcoma is very rare in children. Both tumours may present in a similar fashion, and differentiating them histologically can be difficult. Age cannot be relied upon to accurately predict their behaviour. The tumour karyotype is very helpful in differentiating these neoplasms.