Guide to Canine Anal Gland Tumors

"Canine anal gland tumors are a frequent problem in dogs. They are referred to as perianal gland tumors, dog anal sac tumors, anal polyps or as an adenoma (another name for benign tumor). Another tumor type found in the canine anal area are rectal tumors among others. The tumors are usually primary in nature, meaning they originate in the anal area and did not occur as the result of cancer elsewhere in the body. Tumors can be benign (treatable and not life threatening) or malignant in nature (called adenocarcinoma). Canine anal sac or gland tumors tend to grow slowly and are diagnosed after they result in clinical symptoms that are similar to an impacted anal gland. Diagnosis is based on tests including using fine needle aspiration cytology to take a sample, ultrasound, CT imaging or examination of a biopsy. Treatment involves surgical removal of the tumor followed by antibiotic therapy to avoid infection. The prognosis after surgery is excellent for benign tumors and for malignant tumors it depends on the ability of the surgeon to remove the tumor and how far the cancer spread, if at all."

Canine anal gland tumors in and around the anus (perianal tumors) can be divided into two categories,  perianal gland tumors and anal sac tumors. Rectal tumors are also common in dogs.

Perianal Gland Adenoma: Perianal glands are found anywhere around the anus, at the base of the tail and surrounding the male genitalia. Perianal gland tumors are often benign and occur frequently in male, intact dogs. Female dogs can be affected, however, although Cushing’s disease should be ruled out. These tumors are dependent on testosterone and will often disappear after castration. Multiple tumors can be present. In less than 5 percent of the cases, perianal gland tumors are malignant (fast growing) These tumors can grow fast. Cancerous cells can spread later in the growth process (call metastasis).

Anal Sac Adenocarcinoma: Anal gland tumors (Adenocarcinomas) are usually seen in older female dogs. An anal tumor is very dangerous and can spread quickly to the lymph nodes. This type of cancer creates a secretion that increases calcium in the blood and can damage the kidneys.

Rectal Tumors: Rectal tumors are more common in dogs. They occur in older animals and consist of adenomas, adenocarcinomas, and leiomyomas.

Breeds at Higher Risk


The first sign of this disease is a lump near the anal glands. The area may be red in color. Your veterinarian will do an ultrasound, blood tests and a test of the urine.

Anal gland tumors are often multiple, non painful, relatively solid masses that grow slowly.


The most common treatment for Anal-gland tumors is surgery for removal of the tumor. In some cases surgery is followed by radiation and chemotherapy to ensure that the entire area is treated.  Antibiotics are used to avoid any post operative infection.

If you would like to try homeopathic (herbal) approaches to treatment a good commercial source to explore is PetAlive Formula for Prevention and Treatment of Cancer in Dogs. Herbal remedies are considered to be a supportive treatment vs. a cure in that they help to improve the overall health of the patient while prescription medications focus on the specific area being treated.  This is why they herbal and prescription approaches are often used together. Do not use if a dog is undergoing chemotherapy without consulitng a veterinarian.

Prognosis of Dog Anal Gland Tumors

The prognosis of benign (non cancerous) anal gland tumors is excellent either after castration or after local resection (removal).

The prognosis of malignant (cancerous) anal gland tumors is guarded. Median survival for dogs with anal sac adenocarcinomas was 544 days and dogs with tumors < 10 cm having a significant better prognosis. Also, dogs with hypercalcemia and visible metastases did significantly worse.


Treatment of Perianal and Anal Sac Tumors
J. Kirpensteijn
Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Michael H. Goldschmidt, MSc, BVMS, MRCVS, Diplomate ACVP Professor and Head, Laboratory of Pathology and Toxicology Chief, Surgical Pathology Department of Pathobiology
Frances S. Shofer, PhD, Adjunct Associate Professor of Epidemiology and Biostatistics

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