Single‐aliquot, non‐bronchoscopic bronchoalveolar lavage in the diagnosis of metastatic mammary tumours in dogs

Objective To evaluate the use of bronchoalveolar lavage as an auxiliary tool for the diagnosis of neoplastic lung metastasis from mammary tumours in dogs. Methods A single‐institution prospective observational study including 20 healthy dogs and 30 with mammary tumours. Thoracic radiography and single‐aliquot, non‐bronchoscopic bronchoalveolar lavage with cytology interpretation was performed in all animals and the results compared between groups. Results Dogs with mammary gland tumours and radiographic evidence of pulmonary metastasis had significantly higher relative neutrophil counts in bronchoalveolar lavage fluid than dogs with tumours without evidence of metastasis. In only one dog, in which thoracic radiographs were normal, were malignant cells identified in bronchoalveolar lavage fluid. Clinical Significance Inflammatory bronchoalveolar lavage fluid in dogs with mammary gland tumours may suggest metastatic disease. Bronchoalveolar lavage does not appear to be sensitive for identifying malignant cells.