Fine needle aspiration cytology of the Ewing's sarcoma family of tumors

OBJECTIVE: To study the cytomorphologic features of the Ewing's sarcoma (ES) family of tumors. STUDY DESIGN: During a period of eight years (1990-1997), 123 soft tissue tumors and 65 bone tumors were evaluated by fine needle aspiration cytology (FNAC); 14 cases were diagnosed as in the ES family of tumors. The ages of the patients ranged from 8 to 30 years. All the cases were histologically confirmed. RESULTS: Of 14 cases of the ES family of tumors, 7 were ES, 3 extraosseous ES (EOE), 2 peripheral primitive neuroectodermal tumor (PPNET) and 2 Askin tumor. Cytologically, smears from all the cases showed round tumor cells with a high nuclear/cytoplasmic ratio. On detailed examination, subtle differentiating features were observed. The cells in ES had finer nuclear chromatin in comparison to those of PPNET and Askin tumor, and punched-out clear cytoplasmic vacuoles were present. PPNET showed nuclear molding, unipolar cytoplasmic tags and Homer-Wright rosettes. Histologically, all cases of ES and EOE and one case of Askin tumor showed periodic acid-Schiff-positive inclusions. CONCLUSION: FNAC features coupled with clinical findings enable a rapid diagnosis of the ES family of tumors, from which treatment modalities can be determined.