Transmissible Venereal Tumor, An Infectious Sarcoma
The venereal canine transmissible tumor (CTVT) is a contagious cancer that naturally transmitted between dogs by transferring cancer cells alive during intercourse. This type of disease originated several thousand years ago. However, its characteristics and prevalence still remain unclear and continue to be investigated.
Symptoms
A dog with a venereal tumor usually has a red mass on the membrane of the vaginal surface or on the penis. The tissue mass can break on handling. Drops of blood are also likely to be seen on the foreskin of the penis or in the vagina. In this sense, the animal tends to lick the affected area frequently.
To diagnose this type of tumor, a physical exam is performed that focuses especially on your dog’s genital organs. The vet will need a tissue sample to perform the biopsy. He will also perform standard laboratory tests, including a complete blood count, a biochemical profile, and urinalysis.
This type of tumor rarely spreads to other places, to confirm it, the specialist will make a visual diagnosis that will include x-rays of the chest and abdomen. They will also feel the lymph nodes in the affected area to see if they are reacting to the abnormality. In that sense, a sample of lymphatic fluid will be sent to the laboratory for further evaluation, to determine if cancer cells are in the sample. The presence of cancer cells in the lymph nodes is often a strong indication that the tumor is not benign.
In some dogs, the tumor can go away on its own without any treatment. It can also be surgically removed and medical treatment started after surgery. If the tumor is benign, that is, not cancerous, the prognosis is probably favorable and a complete cure is expected.
The prognosis after medical treatment is usually very good. However, the risks can be much higher if the tumor is found to be malignant. Similarly, cancer therapy has many side effects, especially long-term. For example, the types of drugs used to suppress the growth of cancer cells can affect normal cells, thereby lowering the animal’s immune system. In this sense, it is important for the dog to follow a good nutrition plan to help it recover quickly, without complications.
Finally, your pet’s veterinarian will establish a follow-up plan for further treatment.
Some features
Canine transmissible venereal tumors usually have a cauliflower-like appearance. They vary in size, a nodule can reach millimeters, while large ones can reach 10 centimeters. Its surface is often ulcerated and becomes inflamed and bleeds easily.
Metastasis is rare, it only occurs in 5% of cases. When metastasis occurs, it usually manifests in regional lymph nodes, kidney, spleen, eye, brain, skin, subcutaneous tissue, mesenteric lymph nodes, or peritoneum.
These types of tumors are usually easily diagnosed with an examination, through the histopathological evaluation of the biopsies. It can sometimes be difficult to distinguish from other round cell tumors, such as lymphosarcomas, especially when found at extragenital sites. Although this disease is registered worldwide, its prevalence is relatively high in some geographic regions such as tropical and subtropical urban environments.
Although spontaneous regression can occur, this disease in dogs is usually generally progressive. Treatment consists of surgical removal, radiation therapy, and chemotherapy, although the latter is an option that is considered the choice.
The rate of tumor regression is negatively correlated with the size of the tumor and the age of the animal, especially if it is advanced. In general, complete remission can be expected during the sixth month of treatment.
The prognosis for complete remission with chemotherapy or radiation is good, unless there is involvement in other organs than the skin. Complete surgical excision often cannot be achieved due to the anatomical location of many of these tumors.
