Cytodiagnosis of Ewing′s sarcoma and its confirmation by histopathology and immunohistochemistry

Ewing sarcoma (EWS) is a rare malignant round cell tumor. It is the second common primary tumor of the bone found in children. The most common site in which it occurs is in the pelvis, the femur, the humerus, and the ribs. Due to its morphological overlap, there is diagnostic difficulty and for accurate diagnosis, requires special studies such as immunohistochemistry, electron microscopy, and molecular genetic analysis. We report a case of EWS in a 19 years boy who presented with pain and tenderness of left thigh. Fine-needle aspiration cytology was done and reported as Malignant round cell tumor suggestive of EWS. Diagnosis of EWS was confirmed with special stains and immunohistochemistry.