A large retroperitoneal lipoblastoma: A case report and literature review

INTRODUCTION: Lipoblastoma is a rare benign soft tissue tumor that occurs most commonly in infants and children. However, retroperitoneal lipoblastomas are rare, occurring in <5% of cases. We report a case of large retroperitoneal lipoblastoma and the largest collection of known retroperitoneal lipoblastomas in children in the literature. CASE PRESENTATION: A 3-year-old girl presented with left abdominal mass. Magnetic resonance imaging (MRI) revealed a soft tissue mass measuring 12 × 8 × 6 cm in the retroperitoneal region. The mass had a clearly defined margin and a reticular pattern with an interposing fat component. Based on these findings, the mass was suspected to be a soft-tissue tumor, most likely lipoblastoma. Laparotomy with resection of the retroperitoneal mass was performed. The tumor was easily dissected from the retroperitoneal space without injury to surrounding structure. A histopathological examination demonstrated the mature proliferation of adipocytes and spindle-shaped cells separated by fibrovascular septa accompanied by myxoid changes. The cells were separated into lobules by septa, and areas of immature adipocytes showing a signet-ring or multivacuolar appearance were present at the periphery. Histopathological diagnosis was lipoblastoma. Follow-up at 6 months revealed no evidence of recurrence. CONCLUSION: Retroperitoneal lipoblastoma is rare and tends to be large in size when diagnosed at presentation. Complete resection should not be delayed, as impingement on the surrounding structures is imminent.