[Cytodiagnosis of Ewing sarcoma].

Pelvic Ewing's sarcomas were studied by fine needle aspiration biopsy in two young male patients. Local pain, subfebrility, high ESR had occurred in both cases. X ray examination showed osteolytic lesions in both patients. The differential diagnostic question was, are the lesions osteomyelitis or malignant tumors? Fine needle aspiration biopsies and cytological examinations were performed in order to determine the nature of the lesions. The aspirates consisted of monotonous population of small undifferentiated tumor cells. The nuclei were monomorph with small nucleoli and finely granular chromatin. The tumor cells contained large amounts of PAS positive diastase-digestible granular cytoplasmic glycogen. The aspirated material was examined by immunocytochemistry and electronmicroscopy in one of the cases. Both of these methods had diagnostic value in our patients in the detection of Ewing's sarcoma.