ABSTRACT
Introduction: CD34 Immunohistochemical antigen serves as a tool in differentiating between benign and malignant conditions. Hence, the study was conducted to determine the stromal expression of CD34 antigen by immunohistochemical method in proliferative lesions of the breast and to evaluate the loss of CD34 antigen expression in stromal cells is specific for malignant lesions. Materials and methods: 108 cases of proliferative lesions of the breast were studied from January 2016 to December 2017 for some time of 2 years. Paraffin-embedded blocks were retrieved for all the cases and underwent routine processing followed by Hematoxylin and Eosin staining. 84 cases of the benign lesion, one case of the borderline lesion and 23 cases of the malignant lesion were studied for CD34 immunohistochemical staining, and semi-quantitative assessment was done. Results: On Hematoxylin and Eosin staining, we have found benign lesions includes 63 cases of fibroadenoma, 7, 4, and 3 cases of the fibrocystic disease, fibro adenosis and fibroadenoma respectively with apocrine metaplasia. Malignant lesions include 22 cases of infiltrating ductal carcinoma, one case of infiltrating lobular carcinoma. One case of borderline phyllodes tumor was also included in this study. In normal breast tissue, stroma was positive for CD34 IHC stain. All the malignant cases are showing loss of CD34 staining. Only one case of borderline phyllodes tumor shows grade 2 staining with CD 34 Antigen. Conclusion: We can concluded that the use of CD34 Immunohistochemical marker positivity as an adjuvant tool in differentiating between benign and malignant conditions where the morphology is equivocal.