soft tissue sarcomas appear in different guises and can mimic various reactive soft tissue lesions and epithelial neoplasm thus there is a need for accurate histological diagnosis. Many sarcomas are too poorly differentiated ( undifferentiated ) to exhibit morphological feature specifiec enough to define their histogensis or true origin . So that accurate identification by morphological criteria alone is limited. Histochemical stain and immunohistochemical techniques may help to reduce the size of this category . In this work and besides the routine light microscope, we used a combination of histochemical stain confirmed by immunohistochemical stains to improve accuracy of diagnosis . Also this study aims at evalution of the proliferative activity of different soft tissue sarcomas lesions by silver — stained nucleolor organizer regions which correlate their results with histological type and grade . In this study, 50 biopsy specimens of soft tissue sarcomas received at Pathology Department , Benha University and Histopathology Department of National Cancer Institute in Cairo in three years periods from November 1995 to December 1998 were used .