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Tumors

  • These notes are provided to help you understand the diagnosis or possible diagnosis of cancer in your pet. For general information on cancer in pets ask for our handout "What is Cancer". Your veterinarian may suggest certain tests to help confirm or eliminate the diagnosis, and to help assess treatment options and likely outcomes.

  • An adrenal cortex tumor is an abnormal growth of cells in the adrenal cortex. These tumors result in overproduction of cortisol and can be malignant (cancerous) or benign. In both cases, an adrenal cortex tumor can cause Cushing's disease in dogs. Malignant tumors can metastasize to other organs, including the kidneys, lymph nodes, and thyroid gland. The sooner a diagnosis and treatment plan can be determined, the better the outcome for your pet.

  • Cats have a pair of anal sacs, one located on each side of the anus between the external and internal anal sphincter muscles. The sacs are lined with modified sweat glands called anal glands.

  • The bone marrow is the soft tissue inside the bones. Before birth, the marrow contains the primary (stem) cells that from all the red and white blood cells. After birth, some types of blood cells, particularly lymphocytes, are made in other parts of the body.

  • As continuous improvements in our knowledge and new and evolving methods of treatment are developed, pet owners and their veterinarians have more options available when cancer is diagnosed.

  • A chemodectoma is a type of tumor made up of chemoreceptor cells. Chemoreceptor cells detect chemical changes in the body and respond by regulating chemical or physical processes. These tumors are most often seen along one of the carotid arteries and the aorta. Brachycephalic breeds are more predisposed to these types of tumors, though they may occur in any dog breed. These tumors are usually locally aggressive, however, there are rare cases of metastasis to other organs, including the lungs, lymph nodes, and bone.

  • Chemotherapy is the therapeutic use of chemical agents to destroy, or inhibit the growth and division of cancer cells. Chemotherapy is usually used when tumors are widespread or when there is significant or immediate risk of spread from the primary location. It is often used following the surgical removal of tumors. In some cases, chemotherapy is started prior to surgery. Different protocols are used depending on the drug and the type of cancer being treated. The side effects of chemotherapy are related to the effects of chemotherapy on normal – as well as cancerous – cells. The principal goal with cancer care in pets is to provide cancer control without reducing quality of life. With pets, chemotherapy protocols are purposefully designed so the treatment does not become worse than the disease.

  • Chondrosarcomas arise from cartilage, which is a connective tissue primarily found where bones meet with joints, as well as at other locations in the body (such as the nasal cavity, ribs, etc.). Chondrosarcoma is a rare tumor in cats, but it can occur. The reason why a particular pet may develop this, or any tumor or cancer, is not straightforward. Clinical signs of chondrosarcoma may vary significantly, depending upon where the tumor arises. Although the mass may grow rapidly, less than 20% of feline chondrosarcoma cases metastasize to other parts of the body. Therefore, surgical removal is curative in many cases.

  • All tissues and organs of the body may develop cancer (an abnormal overgrowth of their constituent cells). Every organ (liver, lungs, spleen, kidneys and so on) contains a supporting framework of fibrous connective tissue as well as nerves to relay information to and from the brain.

  • Skin cancers are common in cats, but cutaneous lymphoma is relatively uncommon. Less than 2% of lymphoma cases in cats occur in the skin. As the disease progresses, the skin becomes thickened, reddened, ulcerated, and may ooze fluid. The most common locations to find lesions include the junction between mucus membranes and the skin. Unfortunately, feline cutaneous lymphoma is considered incurable. Surgical removal can be attempted for solitary lesions, although the tumor often returns to the area or will have spread elsewhere in the body already