Thymoma in the dog: two case reports and review of 20 additional cases
Bellah, J.R.; Stiff, M.E.; Russell, R.G.
Journal of the American Veterinary Medical Association 183(3): 306-311
1983
ISSN/ISBN: 0003-1488 PMID: 6885604 Document Number: 211860
A 7-year-old German Shepherd had a large cranial mediastinal mass that had resulted in chronic weight loss. A diagnosis of benign thymoma was made by transthoracic needle biopsy. The thymoma was removed surgically and the dog recovered without complications. At four months after surgery, the dog's activity was improved and it had gained weight. A 12-year-old mixed-breed dog was admitted for evaluation of dependent oedema of the neck. Thoracic radiography revealed pleural effusion and lesions in the right lung and left scapula. Neoplastic epithelial cells were found in a needle aspiration specimen from the scapular lesion. After euthanasia, PM examination showed that the primary tumour, a malignant thymoma, filled the cranial mediastinum and had invaded the cranial vena cava. Metastasis was confirmed in the right lung, liver, and left scapula. Eight cases of thymoma in the dog were retrieved from the Veterinary Medical Data Program. In five of the cases, the tumour was benign. The three dogs with malignant thymoma developed cranial vena caval syndrome, and they were killed or died. Four of the dogs with benign thymoma were killed for reasons unrelated to the tumour. One dog with benign thymoma was free from tumour when examined five years after surgical removal of the tumour.