Small Blue Round Cell Tumors

Abstract

Definition: High-grade malignant poorly differentiated tumor composed of small round cells. The current definition includes several historical entities, such as Ewing sarcoma, peripheral primitive neuroectodermal tumor (PNET), Askin’s tumor (Ewing sarcoma of the chest wall), and adamantinoma-like Ewing sarcoma, all of which share the same oncogenic fusions and similar biologic behavior, and therefore are currently considered as a unique entity defined as Ewing sarcoma family of tumors (EFTs).