[Imaging characteristics of childhood lipoblastoma]

Lipoblastoma and lipoblastomatosis are very rare benign neoplasms, which almost exclusively occur in infants and young children. Despite their potential to local invasion and rapid growth, these tumors have an excellent prognosis, particularly if resected completely. Usually, the diagnosis is not taken into consideration preoperatively, and depends on histopathological evaluation. This study was done to determine imaging characteristics of lipoblastoma.

Eight cases of histopathologically proven lipoblastoma treated from 1988 to 2003 were reviewed, comprising four girls and four boys ranging in age from 17 months to nine years. The localization was chest wall (four times), abdominal wall (once), gluteal region (once), lower leg (once) and forearm (once). Ultrasound, MRI and CT scans were evaluated and correlated to clinical data of the patients.

Ultrasound showed lipomatous echogenicity and echotexture. The tumors appeared signal intensive on T1-weighted MR images and had a mean intensive signal on T2-weighted MR images with fat suppression. They were markedly hypodense on CT. The growth pattern was invasive in all imaging methods, with extension into preformed spaces, such as intercostal spaces and neural foramina, but without infiltration into surrounding structures or metastases.

Ultrasound and MRI are the methods of choice to diagnose lipoblastoma by revealing structures and local growth pattern that appear specific of this rare tumor entity. The imaging characteristics of the lipoblastoma have to be correlated with the age of patients to exclude other conditions in the differential diagnosis.