Significance

• Benign thyroid tumors in cats can cause the thyroid gland to produce too much hormone, which in turn can cause heart failure, liver failure and death.
  
  

Identification

• A thyroid tumor can go completely unnoticed until the cat starts to show signs and symptoms of hyperthyroidism, which can include weight loss, increased appetite, increased activity and hair loss.
  
  

Types

• Thyroid tumors are usually benign in nature, but in rare cases cancerous tumors can metastasize and spread quickly throughout a cat's body.
  
  

Diagnosis

• Thyroid tumors in cats are diagnosed by confirming the secondary condition of hyperthyroidism with blood tests that measure thyroxine (T4) and other hormone levels. Your veterinarian may also do a thyroid scan.
  
  

Treatment

• Treatment options include daily anti-thyroid pills to suppress production of excess thyroid hormones, surgery to remove the tumor (or the thyroid gland) or an injection of radioactive iodine to destroy hyperactive tissue.