Vaginal and Vulvar Tumors in Dogs

Most vaginal and vulvar tumors are noncancerous and have a low rate of metastasis.

Any female dog showing signs of vaginal discharge or tissue protruding from the vaginal opening needs prompt veterinary attention.

Vaginal and vulvar tumors are uncommon and typically occur in older, intact females. Boxers are over represented.

Vaginal tumors may be large enough to interfere with whelping and lead to difficult or delayed delivery of puppies (dystocia).

Tumor formation is multifactorial and a specific cause is not always found.

Leiomyomas are the most common type of benign and account for over seventy-five percent of vaginal tumors.

• Leiomyomas arise from smooth muscle cells lining the vagina.
• Estrogen production by the ovaries in intact females is thought to contribute to formation of leiomyomas.
• Leiomyomas tend to not invade surrounding tissue.

Lipomas are benign tumors arising from fat cells.

• Tend to form in younger dogs
• Boxer are more prone to developing lipomas
• Are typically slow growing and do not metastasize
• An underlying cause is unknown

Fibromas are benign tumors

• Fibromas are usually slow growing
• Arises from fibrous connective tissue
• Chronic irritation may contribute to formation

Transmissible venereal tumors (TVT) are contagious malignant tumors

• Develop via transfer of neoplastic cells
• Most commonly affect the genitals, but can occur in other areas of the body
• Occur most commonly in intact dogs as cells are usually transferred during mating

The most common symptoms are:

• Vulvar discharge
• Tissue protruding from vulva
• Licking of the vulva

Diagnostics include blood work, abdominal ultrasound, thoracic radiographs, and vaginoscopy. Cytology or biopsy of the mass is needed for a definitive diagnosis.

Treatment consists of surgical removal of the mass and usually also includes spaying (ovariohysterectomy). Malignant or large tumors may require aggressive reconstruction of the vaginal and vulvar area. Radiation and chemotherapy after surgical removal are often recommended for malignant tumors.

Vaginal and vulvar tumors continue to grow until they are surgically removed. Surgical removal is more complicated for larger tumors. Prognosis is excellent for benign tumors with complete surgical removal.

Malignant tumors require more extensive intervention and have a more guarded prognosis.

Leiomyomas are the most common type of vaginal tumor and can be prevented by spaying prior to multiple heat cycles. Veterinary guidance is recommended for determining the best age at which to spay an individual dog. No genetic or environmental cause has been found for most other types of tumors.

TVT can be prevented by not allowing direct contact with an infected dog. Spaying helps prevent TVT as most cases of TVT are contracted through breeding.

Most vaginal and vulvar tumors are not contagious. TVTs are the only known contagious canine tumor.

Vaginal and vulvar tumors are uncommon.

Treatment includes:

• Surgical removal of the tumor
• Chemotherapy
• Radiation
• Ovariohysterectomy (spay)