Symptoms of venereal sarcoma in dogs and methods of treatment

Dogs are considered very loving animals, so they often develop sexually transmitted diseases. One of them is venereal sarcoma in dogs - a malignant neoplasm localized on the genitals of a four-legged pet.

However, owners do not need to panic, although the name of the disease contains the word “sarcoma,” it is practically incapable of causing death to the dog. But keep in mind that such a sarcoma can disfigure the animal and deprive it of reproductive capabilities, so it must be treated. The article will discuss this venereal disease, its main signs and symptoms, and will also discuss effective methods of treatment and prevention of this disease.

Classification of sarcoma tumors

Each cancer disease has its own classification, which includes data on the rate of spread of the tumor, as well as its size and shape. In this regard, veterinarians distinguish the following stages of sarcoma development:

1. First stage: the beginning of the manifestation of a mature tumor on the surface of the reproductive organ (tumor size does not exceed 2.5 cm).
2. Second stage: the tumor continues to grow and gradually penetrates the tissues of the affected part of the body.
3. Third stage: the tumor doubles in size, gradually spreading from the lesion to healthy tissue. Your pet's lymph nodes are swollen, this is due to the fact that the tumor is metastasizing.
4. Stage four: sarcoma affects all internal organs of the pet.

Squamous cell carcinoma

Squamous cell carcinoma can develop on a dog's skin and mouth. The skin growth is often discovered by the owners themselves and is very well treated by surgical removal alone, with a small chance - less than 20% - of metastases. Tumors in the mouth that affect the tonsils or tongue are very difficult to remove and sometimes grow to a significant size before they are discovered. Therefore, oral cases of squamous cell disease have a worse prognosis, with less than 10% of dogs with such tumors still alive one year after diagnosis.

Features of the disease

Among veterinarians there is another name for this disease, namely transmissible sarcoma. In appearance it is similar to cauliflower. It is located on the mucous membrane of the dog’s genital organs. The peculiarity of the tumor is that it can spread to the mucous membranes of the nose and mouth, as well as to the conjunctiva of the eye. This happens with the help of the tongue, which the dog uses to lick its genitals.

The pathogen is transmitted from animal to animal during mating. A study of tumor cells showed that it has only a reduced set of chromosomes. The development of pathology takes a long period, spanning from a couple of months to six months. The danger is that vensarcoma does not manifest itself in any way at this time, but the pet is already capable of infecting other animals.

About the importance of a biopsy

In this case, the print clearly shows many homogeneous, discrete round cells with moderate anisocytosis and anisokaryosis (absence/change in size of the cell nucleus, respectively). These cells are distinguished by pale blue cytoplasm, often containing several small, pinpoint vacuoles. Coarse chromatin inclusions and one small nucleolus are visible in the nuclei. Occasional neutrophils, lymphocytes, plasma cells, squamous cells, and red blood cells may also be observed in the microscope's field of view.

Histological examination is important not only in terms of making an accurate diagnosis. With its help, the most effective therapeutic methods are selected, and an adequate prognosis for the further development of the pathological process is given. Simply put, based on these data, you can understand how the tumor will behave in the future. Histopathology also excludes other forms of cancer. In doubtful cases, it is necessary to send samples to clinics specializing in the treatment of oncology. It should be taken into account that even in the postoperative period (or after chemotherapy), the owner will constantly have to bring his pet for repeated sampling, since otherwise a relapse of the disease may be missed.

Causes

Experts are convinced that individuals of any sex and all breeds are susceptible to transmissible sarcoma. According to statistics, infection most often occurs in a pet at the age of 3-4 years. The main factors that can lead to vensarcoma include:

1. Promiscuity of the animal's sexual intercourse.
2. Insufficient attention of the owner in checking the health of the sexual partner chosen for mating with the pet.
3. Weakened immunity and vitamin deficiency.
4. Late detection of the tumor.
5. Therapeutic intervention carried out untimely.

Lymphoma or lymphosarcoma

Lymphoma is the most common type of tumor in dogs and accounts for 20 percent of all canine malignancies. Currently, dogs are 2-5 times more likely than humans to develop lymphoma. This tumor can affect any breed at any age, but golden retrievers are more prone to developing lymphoma.

Symptoms of lymphoma vary depending on which organs are affected by the disease.

Peripheral lymphoma or lymphosarcoma

The most common symptom is enlargement of the peripheral (outside the body cavity) lymph nodes, especially the submandibular, prescapular and popliteal. Owners of such animals sometimes come to the clinic complaining of swollen tonsils. The dog may have no other signs of illness, or may show indirect symptoms such as decreased appetite or lethargy.

Intrinsic lymphoma or lymphosarcoma

Another form of lymphoma affects internal lymph nodes or tissues made up of lymphoid-like cells, such as the liver or spleen. Symptoms of internal lymphoma are often severe and include vomiting, diarrhea, abdominal pain, or difficulty breathing. Left unattended, they can lead to death. Most dogs die within 3-4 weeks if left untreated.

Treatment options for lymphoma may include using a single drug (such as prednisone) or multiple-drug chemotherapy. With the use of prednisolone (a steroid), symptoms may temporarily disappear (usually for 2-3 months). Then the symptoms return. Most dogs (75-90%) respond quickly to multi-drug chemotherapy, achieving remission with a good quality of life for up to 12-16 months.

Symptoms of the disease

It is important for owners to know that bright signs are not typical for the initial stages of the disease. However, an attentive owner may notice that his pet has become more restless, and his urination has become more frequent. Females may lick the vulva and the area around it more often.

The main symptoms of vensarcoma are as follows:

• clearly visible blood clots are released from the penis and genital slit;
• small (from 2-3 mm to 5-6 cm) round tumors of gray or red color appear, they can be single or collected in a cluster;
• the animal’s genitals become red and swollen;
• the prepuce is characteristically thickened;
• the penis and prepuce are diffusely affected;
• in bitches, the vestibule of the vulva is affected, especially on the walls, clitoris and urethra;
• the perineum lengthens, pus protrudes from the genital slit.

It is possible that neoplasms may appear in the pet’s mouth or nose. Vensarcoma creates a lot of inconvenience for the animal, disfiguring the appearance of the pet and not allowing its penis to stand out freely from the prepuce. If this type of sarcoma is diagnosed on time, then it will be quite simple to treat.

Experts note that sometimes there are cases when the tumor resolves on its own. This is typical for young animals, whose bodies are able to produce antibodies that prevent the tumor from progressing.

Risk group by breed

The risk group includes pets leading a free lifestyle or living on the street. For this reason, malignant neoplasm most often affects breeds used for hunting or guard duty:

• royal poodles;
• likes;
• chow-chow;
• shepherd dogs;
• Airedale Terriers;
• bull terriers.

If your four-legged pet is at risk and does not sit within four walls, be sure to follow the recommended preventive measures. They will help reduce the likelihood of infection.

Diagnostic methods

The primary task of the veterinarian is to accurately differentiate venereal sarcoma from prostatitis, which is characteristic of male dogs, and pyometra, which often affects females. A specialist will be helped with this by:

1. Confirming observations: constant discharge of blood from the genital slit and the red color of the lumpy neoplasm.
2. Tumor location: in males on the head of the penis and prepuce, in females - immediately in front of the vagina.
3. The tumor nodes are numerous and soft to the touch, they bleed profusely and are easily damaged.

For further diagnosis, you will need to take a medical history, test the dog's blood and x-ray. The most effective method for making a diagnosis is a puncture biopsy, which is carried out by taking tissue from the affected area of ​​the animal’s genitals.

Etiology

The origin of this tumor has been in question for a long time, and even now there are still unclear aspects. Until recently, some experts foaming at the mouth defended the theory of the viral origin of venereal sarcoma. But recent data confirm that the tumor is, rather, clonal in origin ; infection requires the transfer of neoplastic cells (specifically cells, and not cellular substance from destroyed tissues) from one dog to another. Moreover, today experts are even considering the theory of local susceptibility of animals. When studying this pathology, it was found that venereal sarcoma from Italy, for example, may not be transmitted to a dog, for example, from Bulgaria. The reason is noticeable chromosomal differences in the affected tissues.

Treatment of the disease

Treatment of venereal sarcoma in dogs includes two options: conservative therapy and surgery. The first option is suitable for those pets whose tumors are inoperable. They are required to undergo intensive chemotherapy. However, it must be said right away that this procedure is extremely toxic and has a very negative effect on the dog. Very young and elderly individuals are especially vulnerable to it.

The second option includes the complete elimination of the tumor within the boundaries of healthy tissue. The well-being of surgery depends on whether the animal will bleed during the process. If the tumor is advanced, then the affected vagina will need to be removed and the urethra brought to the abdominal wall. Immediately after the operation, the surgeon will have to apply a three-layer suture to the perineal wound.

Owners should understand that the effectiveness of surgical removal directly depends on how early treatment is started. The features of this method are as follows:

1. The doctor must remove the tumor completely, along with the gland and lymph nodes.
2. The specialist must take care to strengthen the protective reactions of the animal’s body. This will allow the dog to undergo surgery more successfully.
3. During surgery, you should never damage the tumor tissue, as this will cause the tumor cells to spread.
4. The veterinarian is required to repeatedly sterilize surgical instruments during surgery.
5. Bleeding must be carefully controlled and all chances of it occurring eliminated.

During the operation, the animal must be under local or general anesthesia. The dissolved anesthetic cannot be injected into the tumor itself, only into the healthy tissue that surrounds it. If the operation is performed according to all the rules, then relapse is almost impossible.

Post-operative care includes washing your dog regularly, especially the operated areas. They must be kept clean. Do not allow your dog to lick the stitches, as this could introduce an infection there. A special collar placed around the dog’s neck can prevent this from happening. Also watch your pet’s diet; it should include an abundance of vitamins and microelements that can support his weakened immune system.

Prognosis and possible complications

In most cases, the prognosis for a sick pet is favorable. If there are no metastases and the disease is detected at the initial stage, the probability of remission reaches 100%. If the tumor is discovered later, but has not yet reached stage 4, then the probability decreases slightly and reaches 90%.

Despite the dangers of chemotherapy, possible complications are minimal due to the use of low-toxic drugs.

Metastasis of the tumor occurs quite rarely and most often does not extend beyond the lymph nodes. With high immunity, vensarcoma can disappear without treatment - this takes about six months. Also, animals that have recovered from the disease develop antibodies in their bodies that prevent relapses.

Preventive measures

There are no special preventive measures to completely prevent this disease. The most important thing is the attentiveness and caution of the owner towards the person with whom his dog mates. Therefore, you should not be embarrassed to ask the owner of even a purebred and beautiful dog that was chosen for mating whether he has certificates confirming a medical examination. Or about whether she had sexual intercourse with casual sexual partners. If there is no certificate or the individual really “walked” with someone unknown, then it is better to refrain from mating.

If a potentially dangerous contact does occur, the pet owner must thoroughly treat the pet’s mouth and genitals with disinfectants. This can be done using solutions of furatsilin or potassium permanganate. Even after treatment, carefully monitor your pet's genitals. If redness appears on them or blood clots begin to appear, then immediately take the dog to an appointment with a veterinarian.

More radical preventive measures include complete sterilization or castration of the animal. Such a procedure will forever relieve the owner of the worry that his dog may inadvertently contract transmissible sarcoma. And remember, preventing this disease is important not only for your dog, but also for his closest compatriots from the same street or city.

Finally, I would like to say that venereal sarcoma is not so much a terrible disease as an unpleasant disease that can be easily avoided. Show attention and care to your dog, and he will never encounter such pathologies.

What it is?

This is a specific oncological pathology, characteristic only of dogs . Initially it had a focal distribution, but today it is found everywhere in the Caribbean, the USA, southern Europe, Asia and Africa, as well as in some regions of our country. It is transmitted not only through sexual contact, but also through licking contaminated surfaces . Contrary to popular belief, its manifestations, including numerous subcutaneous nodules on the genitals and other parts of the body, occur not only in males, but also in females. It’s just that in males the clinical signs are much more pronounced, and they are brought to veterinarians more often.

What do we know about the causes of the disease? Little is known about the trigger mechanisms specifically. As with any other cancer, the disease is a consequence of mutation of the normal cellular structures of the body . Cancer cells in venereal sarcoma always have an abnormal number of chromosomes (59 instead of the normal 78). It is believed that the “building blocks” for this type of cancer are histiocytes (cells of the immune system), but it is possible that the preceding cells may be others. This issue is still under study.

Protocol for rhabdomyosarcoma

• Dactinomycin - 0.5 mg/m2 once every 3 weeks.

• Vincristine - 0.5 mg/m2 on days 8 and 15.

• Cyclophosphamide - 250 mg/m2 once every 3 weeks. We repeat this course at intervals of 21 days. If owners cannot use dactinomycin, we administer chemotherapy with doxorubicin and cyclophosphamide.

In cats, one of the most aggressive soft tissue sarcomas is post-vaccination fibrosarcoma. Its name is associated with the hypothesis that the cause of this tumor is the adjuvant included in many vaccines. Causing chronic inflammation with proliferation in the injection area, it becomes a trigger for the development of sarcoma. There is also data on the viral nature of the disease and on the genetic predisposition of certain lines of cats to the development of this neoplasm. This tumor exhibits aggressive invasive growth and has a minimum tumor doubling time of 9 days; for comparison, the most aggressive breast tumor has a tumor doubling rate of 30 days. Post-vaccination sarcoma metastasizes infrequently, in less than 20% of cases and, as a rule, in advanced cases or after non-radical surgery when a relapse occurs. Therefore, to cure an animal, it is necessary to diagnose the disease as early as possible and carry out radical surgery. Any veterinarian should develop an oncological alertness and conduct a cytological examination of lumps in cats at the site of vaccination or injection of drugs. Warning signs of the development of fibrosarcoma are:

• swelling that persists for more than 3 months after vaccination;

• compaction more than 2 cm in diameter;

• the lump increases in size 4 weeks after vaccination.

For ablastic removal of this tumor, it is necessary to perform a wide excision of the tumor. The surgical margins should be at least 2 cm from the edge of the tumor, however, this may not be sufficient. There is currently an opinion among some veterinary oncologists that a distance of 5 cm from the visible border of the tumor should be considered safe. The effectiveness of radiation and chemotherapy in addition to surgery for post-vaccination feline fibrosarcoma is currently being studied. In our opinion, adjuvant chemotherapy is justified in the presence of a positive resection margin. There are studies that show an increase in life expectancy in cats using adjuvant chemotherapy with doxorubicin alone, but these data require further study. As a preventive measure and to improve the possible resectability of the tumor, the following measures can be proposed:

• do not inject the vaccine into the area between the shoulder blades;

• administer the rabies vaccine under the skin of the right leg;

• the FeLV vaccine is administered under the skin of the left leg;

• other vaccines should be administered into the right shoulder.