Histopathological and immunohistochemical investigation on diagnosis of canine mammary gland tumors

The main objective of this study was to more reliable diagnosis of canine mammary tumors by using histopathological and immunohistochemical techniques. The tumors were obtained from 43 female dogs in different ages and breeds. Histopathological (hematoxylin and eosin staining) and immunohistochemical evaluations were performed. The final diagnoses were based on histopathological and immunohistochemical examinations. The tumors were diagnosed as in situ carcinoma (3 cases), complex carcinoma (12 cases), tubulopapillary carcinoma (12 cases), solid carcinoma (1 case), spindle cell carcinoma (1 case) and carcinosarcoma (14 cases). The tumors were classified according to WHO-AFIP (World Health Organization?Armed Forces Institute of Pathology) classification.In the immunohistochemical evaluation, monoclonal markers directed against cytokeratin AE1-AE3, calponin, alpha smooth muscle actin and vimentin were used and the results were evaluated semi-quantitatively. Tubular epithelial cells were expressed by cytokeratin AE1-AE3; myoepithelial cells were expressed by calponin, alpha smooth muscle actin and vimentin; osseous and cartilaginous tissues were expressed by vimentin. Calponin performed better than alpha smooth muscle actin for the immunohistochemical demonstration of myoepithelial cells. Differentiations were observed between histopathological and histopathological-immunohistochemical results. Based on these results, only evaluating the histopathological findings may lead to misdiagnosis of canine mammary gland tumors, for this reason, histopathological findings should be supported by immunohistochemical findings was concluded.As a result, the necessity and importance of immunohistochemical techniques in the diagnosis of canine mammary gland tumors revealed in this study.