Vaginal Hyperplasia and Prolapse

What is vaginal prolapse?

If you see excess tissue protruding from the vulva of your female dog, it may be the result of vaginal prolapse or vaginal hyperplasia. These conditions occur during estrus, or the heat cycle, as a result of increased fluid in the tissue of the vagina.

Although vaginal prolapse and vaginal hyperplasia have a similar appearance of a pink, fleshy mass in the dog’s vulva, they are not the same.

A prolapse is where the vaginal tissue is everted, or turned inside out of the body. The process is similar to turning a sock inside out.

Hyperplasia means that there is more tissue than normal due to an increase in cells. Vaginal hyperplasia occurs when the cells in the vaginal wall increase in size and number as a result of stimulation by the hormone estrogen.

A 360-degree protrusion of the tissue lining the vagina may occur in vaginal prolapse. In the case of vaginal hyperplasia, the problem originates from a stalk of the vaginal floor lining. When a hyperplastic vagina prolapses, a round, donut-shaped mass protrudes from the vulva. The prolapsed tissue causes the bitch to strain, which increases the amount of prolapsed tissue.

The prolapsed tissue generally starts out smooth and shiny, but after being exposed, it dries out and can become cracked. The tissue can develop sores and ulcerations, become necrotic, and may require surgery to remove the dead tissue.

Vaginal hyperplasia and vaginal prolapse usually only occur in intact female dogs because spayed bitches do not have enough estrogen in their system to cause the process. However, if a spayed bitch is exposed to estrogen from an outside source, such as licking estrogen cream off her owner’s arm, there is the possibility of hyperplasia and prolapse developing.

Occasionally, when a bitch is pregnant, difficult labor and delivery may lead to a prolapse. The vagina everts outward as a result of the pressure and forces involved in giving birth. During whelping, if you see any type of abnormal vaginal protrusion, you need to seek immediate veterinary care.

Can a bitch with vaginal hyperplasia and prolapse be bred?

Bitches with vaginal hyperplasia but not prolapse usually refuse to let the male breed them. With no prolapse, the breeding can be done by artificial insemination. Prolapsed tissue makes any type of breeding difficult to complete. Extensive vaginal prolapse is rare but has been associated with dystocia, which is the medical term for difficult whelping, and traumatic separation of the dog and bitch during a breeding tie. Supervision of breeding and whelping is important to avoid these serious complications.

Vaginal hyperplasia and prolapse occur most commonly in large-breed dogs, especially in young bitches two years or younger during their first three seasons. The genetics and heritability of the condition are not completely understood. It is definitely challenging to keep a bitch that is prone to vaginal hyperplasia and prolapse in a breeding program.

How can vaginal hyperplasia and prolapse be treated?

The goals of treatment are to keep any exposed vaginal tissue clean and free from trauma. An Elizabethan collar can be worn to prevent self-mutilation.

Unless the vaginal hyperplasia and prolapse are extreme, these conditions will generally resolve on their own as the bitch’s heat cycle ends. In minor cases, the tissue will need to be cleaned and an ointment applied to keep it moist so it doesn’t dry out.

If minimal tissue damage has occurred, your veterinarian may be able to replace the prolapsed tissue back into the vagina. It is first cleaned appropriately and the swelling is reduced by applying a saturated sugar solution. “Purse-string” sutures can be placed in the vulva to hold the tissue in place.

Surgical excision of the prolapsed tissue is not recommended as it is often associated with significant bleeding and does not prevent recurrence during the following seasons.

If the tissue is necrotic, it should be removed surgically. Spaying will prevent another occurrence and can be done at the same time as removing the dead tissue. Bitches with difficulty delivering puppies due to the prolapse will need a C-section.

In some cases, supportive therapy with a diaper and lubricated pad may be helpful. Hormone therapy can be given to make ovulation occur faster and resolve the estrus sooner. Affected bitches can be induced to ovulate with the administration of gonadotropin-releasing hormone (GnRH) or human chorionic gonadotropin (hCG). However, the response to hormones is often minimal and it is ineffective if given after ovulation, but for some bitches, it may be worth a try.

After treatment, the intact bitch should be monitored for a relapse. Vaginal hyperplasia and prolapse do not usually recur after a complete ovariohysterectomy. The only prevention is spaying.

What if I see a protrusion and my dog isn’t in heat?

Vaginal tissue outside of the vulva in a spayed or non-estrus intact bitch may indicate the presence of a tumor. A tumor is an abnormal proliferation of cells. Sometimes, tumors will form inside a dog’s vagina and grow into a larger mass that eventually pushes itself outside the vulva. Vaginal tumors, whether benign or malignant, are not common in dogs, especially if they are spayed.

The tumors can be pedunculated or sessile. Pedunculated means that the growth is on the end of a stalk. These are nearly always vaginal polyps and occur more commonly in intact rather than spayed bitches, although they can develop in both. Polyps are more often diagnosed in older bitches. The growths can be single or multiple.

The term sessile refers to a growth with a wide base of attachment. If the mass is sessile it is more likely a leiomyoma or leiomyosarcoma. An incisional biopsy of the tissue is needed for a definitive diagnosis.

Occasionally, other tumors can occur in the vagina. Growths called transmissible venereal tumors (TVT) will cause vaginal protrusions. TVTs are malignant tumors. Unlike other cancers, TVTs can be spread between dogs. They are sexually transmitted through direct skin-to-skin contact with the tumor that results in cancer cells being spread from dog to dog. This usually occurs during natural breeding but may also be spread by licking, biting and sniffing the tumor.

What is the treatment for vaginal tumors?

The treatment for any kind of mass in the vagina depends on several factors, including the type of tumor (benign or malignant), the exact location, the extent of the mass, and whether it has metastasized to any other location in the body.

If you notice any kind of pink tissue protruding from your dog’s vulva, it is recommended that you make arrangements to see your veterinarian right away.