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Thyroid Tumors and Thyroid Surgery in Dogs

Reviewed by Dr. Peter Kintzer, DVM, DACVIM on Monday, October 19, 2015
Posted October 21, 2015 in Dog Surgery A-Z

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AJ Debiasse, a technician in Stroudsburg, PA, contributed to this article

Your dog’s thyroid glands produce a hormone that regulates metabolism and multiple body functions. Dogs can develop a tumor in one or rarely both thyroid glands, which are located on either side of the beginning of the trachea or windpipe. The tumor is either benign or cancerous. However, most thyroid tumors are malignant (or cancerous) in dogs, and they have a tendency to spread to other organs.

Symptoms of thyroid tumors
The symptoms of thyroid tumors vary greatly. Some tumors become large enough that they are palpable or visible on the neck. If the tumor is large enough, it can push on the trachea or the esophagus (the tube from the mouth to the stomach). If this happens, then you may notice:

In rare cases, cancerous tumors can cause the thyroid glands to produce the hormone in excess, causing hyperthyroidism. Things you would notice at home, in this case, include:

Thyroid tumors are most common in middle-age, large-breed dogs but can occur in all pets. The cause is unknown.

Since thyroid tumors share symptoms with other diseases like airway diseases, metabolic diseases such as diabetes, kidney insufficiency and allergies, it is important to have a full physical exam, full blood work and imaging. If the tumor is large enough, it may be visible on X-rays but a CAT scan is most helpful and can also help determine how invasive it may be.

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Dr. Phil Zeltzman is a board-certified veterinary surgeon and author. His traveling practice takes him all over Eastern Pennsylvania and Western New Jersey. You can visit his website at, and follow him at