Myxoid Lipoblastoma and Mimickers on Fine-Needle Biopsy in a Child

Abstract

Image-guided percutaneous core needle biopsy is a standard and safe procedure for the diagnosis of both solid and hematological malignancies in children. Despite recent improvements, nondiagnosis biopsies persist. Lipoblastoma is a benign adipocytic tumor composed of embryonal fat admixed with mature adipocytes and occurring before the age of 1 year in onethird of cases. Lipoblastoma is usually easily diagnosed, but in some cases, diagnosis may be difficult on percutaneous biopsies, when the lipoblastic component is not well represented or when the tumor contains a prominent myxoid component mimicking other myxoid tumors. We report here a case of lipoblastoma with a predominant myxoid component and discuss differential diagnosis of myxoid lesions of infancy. In such cases, pathologic examination enhanced by adjunct techniques, such as immunohistochemistry and cytogenetic or molecular genetic studies, is needed to achieve accurate diagnosis, particularly on fine-needle biopsies.

Fat-Containing Soft Tissue Tumors in Children, Adolescents, and Young Adults: Which Require Biopsy?

“…Myxoid components may occur in lipoblastomas and therefore should not be considered a pejorative sign unless the age is higher than 10 years. Scarce cases of predominantly myxoid undifferentiated lipoblastomas (some associated with specific PLAG1-HAS2 fusion transcript) [ 20 , 21 , 22 , 23 ] have been reported in children. In such cases, the diagnosis of lipoblastoma cannot be suggested by imaging, and diagnostic biopsy should be recommended as other benign and malignant myxoid tumors may occur.…”