Thyroid Gland Adenocarcinoma in Dogs
The thyroid gland is responsible for a variety of bodily functions, most notably the coordination of hormones and normal metabolism. A particularly malignant form of cancer, carcinoma is characterized by its ability to spread quickly throughout the body. Adenocarcinoma is differentiated only in that it originates in the glandular tissue. Adenocarcinoma of the thyroid gland is a malignant tumor, which can metastasize to other tissue and organs, including the lungs. As iodine is essential for the thyroid to function normally, this neoplasm has been found to be more prevalent in iodine-deficient areas.
Although any breed may be affected, boxers, beagles, and golden retrievers have been found to be at higher risk than other breeds of dogs. Like other carcinomas, it is most commonly seen in older dogs, but it may also occur in young animals.
Symptoms and Types
Following are the symptoms commonly related to adenocarcinoma of the thyroid:
- Large fixed or movable mass over dog’s trachea covering larynx
- Dypnea (difficult breathing)
- Dysphagia (difficulty in swallowing)
- Weight loss
- Dysphonia (hoarseness)
- Polydipsia (increased thirst)
- Polyuria (increased amount and/or frequency of urine passing)
The cause of thyroid adenocarcinoma is still unknown.
Your veterinarian will perform a thorough physical exam on your dog, with blood tests, biochemistry profile, and urinalysis. You will need to give a thorough history of your dog's health and onset of symptoms. The most informative and helpful test is the T4 (thyroxine) and/or free T4 concentration determination. Thyroxine is a primary hormone produced by the thyroid gland. Its level tends to increase in some patients with adenocarcinoma of the thyroid gland. Thyroid Stimulating Hormone (TSH) levels will also be determined, along with T4. TSH is another hormone released from the brain which controls the release of T4 hormone. X-ray and ultrasound imaging, computed tomography (CT) scan, and magnetic resonance imaging (MRI) are some of the diagnostic tools your veterinarian can use to confirm the diagnosis and to determine whether the tumor has metastasized. Your veterinarian may also perform a biopsy of the thyroid tissue to see if malignant cells are present in the thyroid gland.
A gland found in the neck of humans and animals that secretes glands responsible for metabolic rate, calcitonin, and others.
An in-depth examination of the properties of urine; used to determine the presence or absence of illness
The windpipe; it carries air from the bronchi to the mouth
Something that becomes worse or life threatening as it spreads
The process of removing tissue to examine it, usually for medical reasons.
Extreme loss of blood
The voice box; this is one part of the respiratory system
The result of a malignant growth of the tissue of the epithelial gland.