A case of lipoblastoma in a pediatric patient

Abstract

Lipoblastoma is a benign soft tissue tumor that originates from embryonic white fat. Lipoblastoma presents as a slow-growing mass that commonly occurs in the extremities of young children. Histological examination remains the gold standard in confirming lipoblastoma; however, radiology examination can help identify and evaluate the extent and characterization of the mass prior to the excision. Here, we report a 7-year-old male patient who presented with a painless mass in the right popliteal extending to the proximal cruris areas, and the imaging modalities suggested the presence of fat within the mass. The patient then underwent complete excision, and histopathology examination revealed lipoblastoma. This study highlights the possibility of lipoblastoma in older children and the role of imaging examinations in the diagnosis.

Keywords: Lipoblastoma; Lipoblastomatosis; MRI; Pediatric.

Fig. 1

The physical finding of a mass at patient's right popliteal and cruris area, which was noncompressible, painless, and immobile.

Fig. 2

Plain radiography of the right cruris. The anteroposterior (left) and lateral (right) images showed the presence of a heterogenous soft tissue mass (asterisk) without calcification in the right popliteal fossa extending to the proximal cruris.

Fig. 3

(A) Coronal, (B) sagittal, and (C) axial sections of contrast-enhanced CT scan of the right leg revealed a huge mass from popliteal to proximal cruris areas. The mass was multilobulated with mixed fat (asterisk) and solid soft tissue (arrow head) components.

Fig. 4

The presence of fat component was shown by the hypointense signal on fat-suppressed T2-weighted image (asterisk). (A) T1-weighted, (B) T2-weighted, (C) Fat suppressed T2-weighted, and (D) Contrast-enhanced T1-weighted images of the MRI.

Fig. 5

The gross appearance of the mass, which was lobulated and yellowish white in color.

Fig. 6

Hematoxylin and Eosin (H&E) staining. (A) H&E 20x showed lobules of mature fat cells and lipoblasts separated by fibrous septa, (B) H&E 100x showed uni-vacuolated mature adipocytes with nuclei located at the periphery (black arrow), (C, D) H&E 400x showed mature adipocytes (black arrow) and multi-vacuolated lipoblast with hyperchromatic nucleus in the centre (white arrow).

Fig. 7

The patient presented with no mass recurrence one year after the excision (left), which was then confirmed by the follow-up plain radiography (right).