Cytology and Radiology as a Diagnostic Tool to Detect Metastasis in Mammary Tumor Affected Dogs

Abstract

Background: Malignant mammary gland tumors can metastasize to various organs; of which, lungs and regional lymph nodes are most frequently affected. Chest radiographs and regional lymph node FNAs are important diagnostic tool to detect metastasis as per oncology practice guidelines. The present study was aimed to develop suitable diagnostic tool to detect metastasis in mammary tumor affected dogs. Methods: Between September 2017 to July 2018, thirty three dogs (n=33) affected with mammary tumors were included in the study. Out of thirty three dogs, three dogs (n=3) showed swollen regional lymph nodes and pulmonary metastases. Different parameters such as haematology, serum biochemistry, radioimmunoassay, radiology, cytology, histopathology and immunohistochemistry were analysed. Result: TNM clinical staging revealed that all the three dogs showed stage IV tumors which were usually malignant and showed frequent metastases. Haematological abnormalities such as anemia, leucocytosis and reduced platelet count were noticed. Serum biochemistry showed reduced protein and electrolyte level with elevated alkaline phosphatase and alanine transaminase. Radioimmunoassay showed many-fold elevation of estradiol and progesterone. Radiography of lungs revealed severe pulmonary metastasis. Cytological examination of swollen accessory lymph node revealed mixed population of lymphocytes and neoplastic cells. Grossly, the lymph nodes were found to be enlarged, blood tinged and covered with subcutaneous adipose tissue. Histopathology of tumor masses from three dogs revealed cystic papillary carcinoma, ductal carcinoma and anaplastic carcinoma. Immunohistochemistry revealed that dogs were affected with triple negative tumors which were highly malignant, poor prognosis and not responding to therapy.