Computed tomography of a cat with primary intratracheal lymphosarcoma before and after systemic chemotherapy.

A 12 yr old male neutered domestic shorthair cat presented with worsening tachypnea of 1 mo duration and open mouth breathing. Radiographs revealed tracheal narrowing at the thoracic inlet. Computed tomography (CT) revealed a contrast enhancing 8-cm long fusiform mass within the dorsal tracheal membrane. Tracheobronchoscopy confirmed the presence of the tracheal mass at the thoracic inlet, and lymphoma was diagnosed based on uniformly atypical lymphoid cells on aspirated bronchoalveolar lavage fluid. The cat was treated with combination chemotherapy consisting of cyclophosphamide, vincristine, doxorubicin, and prednisolone. Thoracic radiographs and CT performed 1 mo after completion of the 6 mo chemotherapy protocol revealed resolution of the tracheal mass. The cat remained clinically normal at 21 mo after treatment.