Which of the following immunohistochemical markers would be expected to be positive in biopsies of Ewings Sarcoma?
S-100 protein and neuron-specific enolase, both of which are markers for tumors with neuroendocrine differentiation, are usually positive in Ewing sarcoma. The tumor also usually contains glycogen, which can be helpful in the distinction with other "small blue cell tumors" (including lymphomas, neuroblastoma, and Wilms tumor) of childhood. GOOD TO KNOW: CD3 is a T cell marker. CD21 is a B-cell marker. Myogenin is a marker for rhabdomyosarcoma. Ewing sarcoma: It typically involves the diaphyseal region of long bones and also has an affinity for flat bones. The plain radiograph may show a characteristic "onion peel" periosteal reaction with a generous soft tissue mass, which is better demonstrated by CT or MRI. The presence of p30/32, the product of the mic-2 gene (which maps to the pseudoautosomal region of the X and Y chromosomes) is a cell-surface marker for Ewing's sarcoma (and other members of the Ewing's family of tumors, sometimes called PNETs. Ref: Patel S.R., Benjamin R.S. (2012). Chapter 98. Soft Tissue and Bone Sarcomas and Bone Metastases. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.
CD3
CD21
Myogenin
S-100