This report describes the morphological and immunohistochemical findings of a case of mammary gland pleomorphic lobular carcinoma occurring in the canine species. Histologically, it was characterized by the presence of tumor cells loosely dispersed in the stroma or arranged in a linear pattern showing relatively abundant eosinophilic cytoplasm with an eccentric nuclei. These morphological features, characteristic of pleomorphic mammary gland lobular carcinoma in woman, were not previously described in dogs.
Dog; mammary carcinoma; mammary gland; pleomorphic lobular carcinoma