Thyroid neoplasms in the dog. A clinicopathologic study of fifty-seven cases

The paper summarizes the features of adenomas and carcinomas of the thyroid gland in dogs. Only the Boxer breed was significantly over-represented. No sex incidence was apparent. The average age was 10 years in 29 dogs with adenomas and 9.6 years in 28 dogs with carcinomas. Adenomas were small, grew slowly and compressed surrounding parenchyma; most were detected incidentally post mortem. Thyroidectomy for adenoma was carried out in ten dogs; uneventful survival was recorded in five of these for periods ranging from 4 months to 2 years. Adenomas were all of mixed solid and follicular type. Carcinomas grew rapidly, produced extensive local invasion and distant metastases, principally to lungs. Four dogs with carcinoma were thyroidectomized and three of these survived without recurrence of tumor for 1, 1.3 and 3 years; most carcinomas were inoperable. Three of the carcinomas were anaplastic; the remainder were well differentiated and contained solid and follicular elements.