Swainson S.W., Nelson O.L., Niyo Y., et al.
Right lateral and dorsoventral thoracic radiographs were made at the time of initial presentation (Fig. 1). A well circumscribed soft tissue mass was identified within the cranioventral mediastinum. The remaining structures in the thoracic cavity appeared normal. Because the cat had no clinical signs of disease the owner decided not to pursue further diagnostics. The cat was discharged with the recommendation to return for reexamination and radiographs. Follow-up thoracic radiographs were made two months later. Subjectively, a slight decrease in space between the dorsal margin of the mass and the trachea was noted on the lateral view compared to the initial radiograph. Overall, size of the mass was relatively unchanged. Physical examination including thoracic auscultation was normal.