A large retroperitoneal lipoblastoma as an incidental finding: a case report

The study is published in the BMC Pediatrics.

Lipoblastoma is a rare benign mesenchymal neoplasm of infancy that most commonly occurs on the extremities and trunk but can arise at variable sites of the body. Retroperitoneal lipoblastomas are particularly rare but can grow to enormous size, and preoperative diagnosis is difficult with diverse, mostly malignant differential diagnoses that would lead to aggressive therapy.

Since lipoblastoma is a benign tumor that has an excellent prognosis after resection, correct diagnosis is crucial.

Hence, the authors studied a case report of a 24-month old infant who presented with a large retroperitoneal tumor that was clinically suspicious of a malignant tumor. Due to proximity to the right kidney, clinically most probably a nephroblastoma or clear cell sarcoma of the kidney was suspected.

Radiological findings were ambiguous. Therefore, the mass was biopsied, and histology revealed an adipocytic lesion. Although mostly composed of mature adipocytes, in view of the age of the patient, the differential diagnosis of a (maturing) lipoblastoma was raised, which was supported by molecular analysis demonstrating a HAS2-PLAG1 fusion.

The tumor was completely resected, and further histopathological workup led to the final diagnosis of a 13 cm large retroperitoneal maturing lipoblastoma. Surgery was planned after which the child recovered promptly from surgery and showed no evidence of recurrence during the subsequent follow ups.

Therefore, the authors concluded that "Although rare, lipoblastoma should be included in the differential diagnoses of retroperitoneal tumors in infants and children, and molecular diagnostic approaches could be a helpful diagnostic adjunct in challenging cases."