Adipose and myxoid tumors of childhood and adolescence.

Adipose and myxoid tumors in children are an unusual and challenging group of neoplasms that have some unique aspects in contrast to these tumors in adults. Less than 10% of soft tissue neoplasms in the 1st 2 decades of life have an adipose phenotype and most are benign. The most common are various types of lipoma and lipoblastoma. Liposarcoma in young patients is rare and has a distinctive distribution of histologic subtypes, including classic myxoid liposarcoma, and unusual variants, such as pleomorphic-myxoid liposarcoma. Pathologic examination enhanced by adjunct techniques, such as immunohistochemistry and cytogenetic or molecular genetic studies, is useful for classification of difficult cases. Myxoid tumors can overlap with adipose tumors and are included in this review because of the morphologic similarities and importance of diagnostic accuracy. This article reviews the clinicopathologic features of adipose and myxoid tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents and the differential diagnosis.