Metastasis of a Mammary Gland Carcinoma in a Dog

Mammary cancer is the most common malignant neoplasm in the bitch. It constitute 40 percent of all tumors in female dogs, which is three times higher than incidence of mammary tumors in humans[2]. Cytological differentiation between benign and malignant canine mammary tumors is difficult, however, an irregular chromatin pattern was reported to be a significant criterion for malignancy[1]. It can be estimated that approximately 30 percent of the surgically removed mammary tumors are malignant[4]. Malignant mammary tumors often have some degree of infiltrative/destructive growth into adjacent tissues and/or invasion of vessels. Malignant mammary tumors often metastasize into local lymph nodes and lungs, and less frequently into other organs[3]. Based on histological and cytological criteria, this case was diagnosed as tubulopapillary carcinoma of the mammary gland. (omitted)