Féline-Thorax : A case of cranial mediastinal mass in a cat

Male castrated cat of 1,5y old.
Presented for dyspnea since 1 week.
On auscultation, the respiratory and cardiac sounds are muffled.
The dyspnea is more pronounced in expiration.
The trachea is severely deflected dorsally. The carina reaches the 8th intercostal space. The trachea is flattened and parallel to the spine by a soft tissue opacity occupying the ventral part of the thorax. This opacity mask the cardiac silhouette. The lung lobes are retracted dorsocaudally and the ventral margins are rounded. The costodiaphragmatic recesses are rounded. Multiple interlobar fissures are visible on the VD view.
The cranial abdomen shows no abnormalities. The diaphragm is intact.

Pleural effusion associated with a cranial mediastinal mass

DD: 1 / lymphoma
2 / thymoma
3 / Other (thyroid carcinoma, abscess, hematoma)

The cat is FelV positive and lymphoma is strongly suspected.
An ultrasound of the mediastinum shows lymph nodes increased in size and a fine needle aspiration cytology revealed a lymphoma.