Ewing sarcoma family of tumors

Last revised by Dr Mohamed Saber on 04 Apr 2021

The Ewing sarcoma family of tumors are a group of small round blue cell tumors that are closely histogenetically related, all demonstrating non-random t(11;22)(q24;q12) chromosome rearrangement resulting in the formation of the EWS-ETS fusion gene 1-3


Although the literature is littered with contradictory terminology, all three tumors are likely to represent the same entity with minor differences in differentiation. For example, PNET is more differentiated demonstrating neural elements (e.g. Homer Wright rosettes) 2. As such all three entities should be referred to as Ewing sarcoma, with pPNET/Askin representing extraskeletal Ewing sarcoma.


The Ewing sarcoma family of tumors include:

  1. Ewing sarcoma of bone
  2. extraosseous Ewing sarcoma (EES)
  3. peripheral primitive neuroectodermal tumor (pPNET)
  4. Askin tumor
  5. neuroepithelioma

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Cases and figures

  • Figure 1: histology : small round blue cells
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  • Case 1: Ewing sarcoma of the rib
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  • Case 2: Ewing sarcoma of the chest wall
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