Unusual histological variant of Ewing's sarcoma of mandible.

Ewing family of tumors (EFTs) comprise highly malignant, nearly undifferentiated neoplasms including Ewing's sarcoma (ES), primitive neuroectodermal tumor (PNET) and a spectrum of other unusual variants. In general, EFTs are included among small blue cell tumors. Establishing histological diagnosis can be difficult; CD99 and FLI1 immunohistochemical staining has improved diagnosis, but these markers are not specific for EFTs.