CD34 expression immunohistochemistry contributes to the differential diagnosis of soft tissue tumours

CD34 is a myeloid progenitor cel antigen and present in endothelial cells and almost all vascular lesions. Additionally, CD34 has been described in numerous fibroblast-like cells and different mesenchymal rumours. The immunohistochemical evidence of CD34, however, may be of importance in the differential diagnosis of benign and malignant soft tissue lesions, if clinicopathological features and other immunohistochemical markers are regarded properly. We studied the CD34 immunopositivity of solitary fibrous tumour at different sites (11 out of 11 tumours tested stained positive), dermatofibrosarcoma protuberans (15 out of 18 stained positive), and gastrointestinal stromal tumour (15 out of 15 stained positive), and discuss the significance of these results in differential diagnosis to morphologically comparable soft tissue lesions.