Computed tomography characteristics and complete resection of large thymoma in a cat

Thymoma is an intrathoracic malignant tumor occurring rarely in cats. Although surgery is the treatment of choice in feline thymomas,complete resection may be difficult in cases that the large vessels are involved into the mass.Therefore,diagnostic imaging techniques including computed tomography( CT) are essential for the treatment of feline thymomas. This report aimed to present the CT characteristics and successful removal of very large thymoma in a cat with exfoliative dermatitis.An 8-year-old spayed mongrel cat was referred to our hospital with chief complaints of chronic anorexia,alopecia,and desquamation. Tachypnea,tachycardia,and exfoliative dermatitis were observed in the first presentation. Thoracic radiography showed a very large mass in the craniomediastinal region. In the CT findings,the mass included multiple small cysts,and forced up the intrathoracic trachea,cranial vena cava,brachiocephalic trunk and left subclavian artery as well as heart and lungs.On the 6th day after,the patient underwent a median sternotomy and diaphragmatic incision to expose the mass. The mass was completely resected with right phrenic nerve by using cautery and LigaSure. No postoperative complications were observed. The histopathologic diagnosis was made as a thymoma. Postoperative progress of the patient was excellent without the exfoliative dermatitis.Extremely enlarged thymoma could be completely resected in this patient,and the exfoliative dermatitis was postoperatively controlled. The paraneoplastic immune disorder was suggested to cause the dermatitis. CT has a great impact on the indication of surgery for the feline thymomas.