Cytologic analysis of bronchoalveolar lavage fluid from 47 dogs with multicentric malignant lymphoma

Bronchoalveolar lavage (BAL) was performed in 47 dogs with multicentric malignant lymphoma (ML). Cytologic results were evaluated, and ability to detect pulmonary involvement with ML, using BAL, was compared with ability to detect pulmonary involvement, using thoracic radiography and tracheal wash. Lung lobes were considered to be involved with ML on the basis of BAL fluid findings if morphologically abnormal lymphocytes were present in the fluid. Total nucleated cell count, relative lymphocyte count, and absolute lymphocyte count were greater (P < 0.001) in BAL fluid from dogs with multicentric ML than in BAL fluid from histologically normal dogs. Pulmonary involvement with ML was detected by BAL fluid cytologic examination in 89 of 135 lung lobes lavaged (66%). Lung lobes involved with ML were from 31 of the 47 dogs with multicentric ML (66%). Radiographic abnormalities supportive of pulmonary parenchymal involvement with ML were detected in 16 of the 47 dogs (34%). Of these 16 dogs, 15 (94%) had pulmonary involvement with ML on the basis of BAL fluid cytologic findings. Tracheal wash fluid contained abnormal lymphocytes in 4 of 41 dogs (10%). In all 4 dogs, BAL fluid also contained abnormal lymphocytes. Cytologic evaluation of BAL fluid was more sensitive in detecting pulmonary involvement with ML, compared with radiographic evaluation of the lungs or tracheal wash.