Intestinal Tumor in Cats

Intestinal tumors are most likely to occur in middle-aged to older cats who are over six years of age. Male cats are more likely to develop intestinal tumors than females.

Though uncommon, there are a variety of tumors that can develop in the large and small intestines in cats. These include adenocarcinoma, malignant tumors that affect the gastrointestinal tract; lymphomas, a type of cancer that originates in the lymphocyte cells of the lymph nodes; leiomyosarcomas, a painful type of cancer that occurs in the intestines; mast cell tumors, which originate in the skin; carcinoid tumors, which develop in the mucous lining of the intestines; gastrointestinal stromal tumors (GIST), which begin in the mesenchymal cells in the intestines, and leiomyomas, benign tumors that develop from the smooth tissue in the intestines.

Symptoms vary slightly, depending on the type of intestinal tumor that is affecting the cats and where in the gastrointestinal tract it begins forming. Malignant tumors that have spread to other organs in the body may also present varied symptoms. Common symptoms include:

• Excessive gas (flatulence)
• Vomiting, perhaps with blood
• Loss of appetite
• Weight loss
• Rumbling noises from abdominal area (borborygmus)
• Hardened mass felt in abdominal area
• Straining to defecate (tenesmus)
• Black colored stools (melena)
• Distended loops of small bowel that are painful
• Weakness due to low blood sugar
• Stools that have bright red, bloody streaks
• Protrusion of rectal wall through anal cavity (rectal prolapse)

There are no known causes of intestinal tumors. Because they are normally found in older cats, researchers believe that they could form due to a mutation during cell division. The older a cat is, the greater the number of cell divisions that have occurred, increasing the likelihood of a mutation that causes a tumor to form.

The veterinarian will perform a physical exam of the cat, feeling for any masses in the abdomen and placing a gloved finger into the rectum in order to feel for any palpable masses in the rectum and anus. The veterinarian will need to know the cat's health history and a detailed list of symptoms in order to correctly diagnose the leiomyoma. 

More common gastrointestinal conditions, such as pancreatitis, parasitic infections, obstruction from a foreign body or inflammatory bowel disease, must be ruled out in order for the cat to receive a proper diagnosis. Tests to rule these conditions out will include a biochemical profile, complete blood count and a urinalysis. A fecal test to look for the presence of blood in the stool will also be completed. An abdominal ultrasound will also be performed. The abdominal ultrasound will be used to look for any masses or thickening of the tissue in the bowels or stomach, which is indicative of a tumor. The veterinarian may also use the ultrasound to guide a thin needle into the cat's abdomen, taking a sample of the fluid in order to look for cancer cells.

A special test that uses dye, known as gastrointestinal contrast radiography, may also be performed. Prior to the test, the cat will be given an oral dose of a dye solution called barium. The dye illuminates the gastrointestinal tract during X-rays. Multiple X-rays will be taken of the gastric tract as the barium passes through the cat's digestive system. This allows the veterinarian to look for and identify the tumor. Rarely, an endoscopy may be performed. During the endoscopy, a small, flexible tube with an attached camera will be inserted into the stomach and/or the rectal area to help the veterinarian visualize the tumor.

Surgery

Surgery is the most commonly used treatment for intestinal tumors. The veterinarian will make a small incision into the abdomen in order to remove the tumor. The portion of the intestines that contained the tumor will be removed and the intestines will be resected. The incision will then be closed with sutures.

Dietary Changes

The veterinarian may place the cat on a specific diet that will consist of frequently eaten small meals that are easily digestible and high in nutrition. This diet will allow the food to pass through the digestive tract more easily and help the cat to get the nutrition it needs without food becoming obstructed.

Medication

The cat will be prescribed painkillers in order to control its pain from the tumor. Chemotherapy, a medication used to kill cancer cells, is sometimes recommended but is often not successful.

Because intestinal tumors often metastasize to other parts of the body and grow quickly, the prognosis is typically poor. If surgery occurred, the cat will need to wear an Elizabethan cone in order to prevent it from biting its sutures. The veterinarian will need to follow up with the cat to ensure that the incision site is healing well and is free from infection. At each follow-up appointment, a physical exam and ultrasounds will be taken to monitor the intestines for any tumor re-growth.