Cytodiagnosis of metastatic Ewing's sarcoma of orbital mass and its confirmation by demonstration of EWS/friend leukemia integration 1 fusion gene.

Ewing's sarcoma (EWS) is an undifferentiated sarcoma of bone. Its morphologic appearance resembles many other malignant small round cell tumors. Due to the morphologic overlap, there is diagnostic difficulty and for accurate diagnosis, requires special studies such as immunohistochemistry, electron microscopy, cytogenetics, and molecular genetic analysis. We report a case of metastatic EWS from orbital mass in a 14-year-old female child diagnosed by cytology after clinicopathologic evaluation. She presented with low back ache of 1 year followed by proptosis of the right eye and swelling of the right side chest wall. Cytosmear and Tru-cut biopsy was taken from the orbital mass showed features of EWS. It was confirmed later by further studies including demonstration of EWS/friend leukemia integration-1 fusion gene by molecular genetic analysis.