Ewing's sarcoma pathophysiology

Overview
Ewing's sarcoma is the result of a translocation between chromosomes 11 and 22, which fuses the EWS gene of chromosome 22 to the FLI1 gene of chromosome 11. This abnormal gene caused by the translocation can in fact be found using DNA testing. This abnormality does not appear to be genetically linked, and it is exceedingly rare to have two cases of Ewing's Sarcoma within the same family.

Microscopic pathology
The composition of Ewing's sarcoma consists of a homogeneous population of small round cells that have a high nuclear to cytoplasmic ratio. Also, the population of small round cells are arrayed in sheets. There is a presence of scant cytoplasms which are pale, vacuolated, and are characterized by their faded boundaries. The nuclei have intense color which make them easily visible. Mitotic activity is usually low within these cells, and cytoplasmic glycogen is also usually present.