Today’s case is a 12-year-old female neutered German Shepherd cross with coughing for one week. What are your differential diagnoses?
On all three radiographic projections, there is a cavitary mass in the right caudal lung lobe. It is best seen on the left lateral projection and contains soft tissue opacity as well as gas lucency. On the d/v projection, the soft tissue opacity is on the lateral side of the lesion, indicating that it may be tissue rather than fluid. The remainder of the thorax appears normal.
CT images in a lung and soft tissue window are available. The mass is cavitary and contained within the right caudal lung lobe. The contents are soft tissue with mineralized material and a small fluid component, as evidenced by the horizontal gas fluid interface in the lower right portion of the mass.
- focal bronchiectasis
The mass is visible best on the left lateral projection because the right lung is then filled with air, providing better surrounding contrast. If you were suspicious of fluid contents of the mass, a horizontal beam radiograph could help to diagnose this.
Given the age of the animal, a primary lung tumor is the most likely differential diagnosis.