Vet Patho129:552-553 (1992) Mammary Carcinoma with Peritoneal Metastasis in a Cow

In contrast to the dog and cat, mammary neoplasia is rare in the cow. A review of the literature by Ford et al. ' revealed only 41 cows with primary mammary gland neoplasia since 1902. Ten of those cases involved mammary carcinomas. This report is of an additional case of mammary carcinoma with an unusual pattern of metastasis. An 8-year-old Simmental cow was recumbent for a day before dying. The carcass was submitted for necropsy 12 hours after death. The left front quarter of the mammary gland was uniformly firm and pink on incision, but was not enlarged. The other three-quarters were soft and tan. The peritoneal cavity contained approximately 4 liters of light yellow, clear fluid. Numerous white nodules, approximately 2 ern in diameter, were distributed throughout the mesentery and adhered to the serosal surfaces of the liver, spleen, an