Thyroid Carcinoma in Dogs

Thyroid carcinoma in dogs refers to a tumour arising from the cells of the thyroid gland, the small paired organ in the neck that produces hormones regulating metabolism. These tumours tend to grow locally and can, in some cases, spread to other parts of the body. They are uncommon, and most often recognised in middle-aged to older dogs. Owners may notice a lump or swelling in the lower neck, changes in bark or breathing sounds, or difficulty swallowing. In some dogs, the first sign is a change in energy or weight that does not fit the usual pattern. Occasionally, thyroid carcinoma is found during investigation of other concerns, before any visible changes have appeared. This page explores what signs may be observed, what is happening in the tissue beneath, how thyroid carcinoma is investigated through imaging and sampling, and the range of approaches that exist—from surgery to other options when surgery is not straightforward. The goal is to help orient understanding, not to advise on any individual animal.