Cat with a Tracheal Mass

A 7 year old castrated male domestic shorthair cat was evaluated for a three month history of progressive, intermittent respiratory distress.  Four months prior to evaluation he developed a dry, hacking cough.  Thoracic radiographs at that time revealed a thoracic inlet tracheal mass. The cat responded initially to antibiotic therapy (amoxicillin trihydrate/clavulanate potassium; Clavamox) and prednisone.  In the months prior to presentation, his episodes of respiratory distress were intermittent, and he was able to be managed with periodic injections of dexamethasone and oral prednisolone.   One week prior to evaluation his clinical signs were no longer amenable to medical management and he developed progressive respiratory distress.
On examination, the cat had inspiratory and expiratory wheezes audible from a distance with an increased respiratory rate and effort.   Thoracic auscultation revealed marked referred upper airway noises which when combined with his increased axillary temperature of 103F, was consistent with upper airway obstruction and failure to dissipate heat.
Serum biochemistry and complete blood count were unremarkable aside from mild anemia.
Only lateral thoracic radiographs could be obtained due to the cat’s respiratory compromise,  which are shown below.

Based on these radiographs, what are the differentials for the tracheal soft tissue opacity?
What further diagnostics could be performed to obtain a diagnosis of this mass?  Of these diagnostics, what risks are associated with the procedure?
What are the options for management of this tracheal mass?
Tracheoscopy was performed, which requires extubation in cats.  The following image was obtained at the level of the thoracic inlet, with dorsal being at the top of the image.  Cystology and histopathology samples were obtained via the working channel of the scope.  Cytology revealed neutrophilic, histiocytic and lymphoplasmacytic inflammation and mild epithelial atypia.  The degree of atyptia was felt to be expected for dysplasia secondary to chronic inflammation.

Do these cytological findings rule in or rule out a diagnosis?
Based on the mass location, tracheoscopy findings, and cytology results, what are the management options for this cat?
Tracheal stenting was felt to be the best option for the management of an intrathoracic tracheal mass, given that it was not in an ideal location to be surgically resectable, and its broad based nature precluded removal via trachescopy.

Should the stent have been positioned differently based on the appearance of the mass radiographically and fluoroscopically?

Tags: cases

Category: Cases, Endoscopy, Respiratory