Metastasis of Canine Inflammatory versus Non-Inflammatory Mammary Tumours

Summary Inflammatory mammary cancer (IMC) is the most aggressive and lethal type of mammary cancer in women and dogs. The aim of this study was to determine whether the pattern of metastasis for canine IMC differed from that for canine non-inflammatory malignant mammary tumours (NIMMTs). Samples from a total of 72 intact female dogs were evaluated in the study. Thirty-nine of these dogs had IMC and 33 had NIMMTs. Different patterns of metastasis were observed between the groups. Metastases to the urinary bladder and reproductive tract were found only in dogs with IMC. In contrast, IMC never metastasized to the bone and there was less frequent metastasis to the lungs, liver and kidney. This metastatic pattern in IMC supports the hypothesis that this form of mammary neoplasia has a distinct pathogenesis. These data have clinical relevance and the observations may have value in consideration of the fact that canine IMC has been proposed as a natural model for the study of human inflammatory breast cancer.