Resumo (EN)
Spontaneous mammary tumors are the most common neoplasms in the intact adult female dog. The malignant tumors account for up to 50% of cases, that frequently metastasizes to regional lymph nodes, lungs, liver, kidneys and, less frequently, bones. In human breast pathology immunohistochemistry is routinely used with diagnostic, prognostic and predictive purposes. The aim of this study was to compared immunolabelling of histological specimens with conventional staining in the detection of nodal micrometastases from dogs with mammary carcinoma. A series of 51 lymph nodes from 47 dogs with carcinomas were evaluated by staining with haematoxylin and eosin and immunohistochemically for antibodies to pan-keratin. The immunohistochemical test detected occult micrometastases in 6,8% of the lymph nodes previously negative by haematoxylin and eosin staining. This study indicated the value of immunohistochemical labelling for the detection of epithelial metastases in canine lymph node samples.