Radiographic appearance of pulmonary metastases from transitional cell carcinoma of the bladder and urethra of the dog.

Eleven cases of histologically proven transitional cell carcinoma of the bladder or urethra of the dog were selected for evaluation and characterization of the varied radiographic appearances of the lungs. In the 8 dogs with metastases, those appearances included radiographically normal pulmonary parenchyma, a semidense, diffuse, lacelike haze referred to as interstitial opacity, nodular interstitial opacity, and consolidations. One affected dog had hilar lymphadenopathy. In the 3 dogs without pulmonary metastases, the radiographic appearance was either normal pulmonary parenchyma or increased unstructured interstitial opacity. Of all dogs in the study, 6 had a radiographic appearance of increased unstructured interstitial opacity. Four of those 6 had histologically proven metastases in the peribronchiolar lymphatics or alveolar capillaries. Dyspnea was not identified in any of the affected dogs. The radiographic appearance for 3 of the 8 dogs with pulmonary metastases was misinterpreted as opacity compatible with age. The radiographic appearance for 1 of the 3 dogs without pulmonary metastases was misinterpreted as highly suspect for metastases.