Lipoblastoma of the extremities.

Background: Lipoblastoma is a rare benign tumor of infancy and childhood, with similar radiographic imaging findings as malignant liposarcoma. Therefore, it is crucial to distinguish through other diagnostics and clinical features. We present our experience with the diagnosis and clinical management of this entity.

Methods: A retrospective chart review was performed to identify children treated for lipoblastoma at our institution over a 30-year period. Charts were evaluated for diagnostic methods, treatment, and recurrence risk.

Results: A total of 9 males and 3 females were identified. The age at diagnosis ranged from 8 months to 44 years. Imaging modalities employed included ultrasound (N = 5), MRI (N = 12), X-ray (N = 8), and CT (N = 3). The tumor location was reported in the lower extremity (N = 8) and upper extremity (N = 4). The tumor size ranged from 1.7 to 18 cm (mean=7.08 cm). All patients underwent complete resection. Available pathology reports noted masses featuring mature adipocytes (N = 1), fibrous septa (N = 2), focal myxoid changes (N = 1), and spindle cells (N = 2). Nine patients underwent chromosomal analysis, which demonstrated five chromosome 8 abnormalities. No recurrences were reported. Three patients had follow-up imaging, and 11 had follow-up visits between 2 weeks to 15 years.

Conclusion: Lipoblastoma is an uncommon childhood neoplasm of embryonic white fat that can also be present in adolescence and adulthood. Imaging, especially MRI, is helpful in limiting the differential diagnosis, but definitive diagnosis requires tissue biopsy, which should be obtained with core biopsy rather than fine needle aspiration. Surgical resection is curative with few complications. We do not recommend routine monitoring as recurrence is unlikely.