Testicular cancer in a dog: symptoms and treatment [veterinarian's recommendations
Testicular tumor in a dog
Cancer diseases are the bane of our times - genetic conditions, some diseases, inadequate diet, environmental pollution, the use of pesticides, preservatives are just some of the factors that may affect deformation and disturbances in the functioning of cells, leading to the formation of neoplastic changes.
The increasing incidence of cancer is a problem not only for humans, but also for animals. Veterinary oncology is a rapidly developing field that allows you to extend life and increase its comfort in animals suffering from cancer.
Is it possible to somehow avoid cancer? In some cases, yes - an example would be testicular cancer, because castration at the right age protects your dog from it.
- The structure of the dog's testicle
- Predisposition in the testicle in the dog
- Testicular tumor in dog, clinical signs
- Sertoli support cell tumors
- Interstitial-Leydig cell tumors
- Germ cell tumors-seminomas
- Other cancers
- Treatment of testicular tumor in dog
- Prognosis of testicular tumor in dogs
The structure of the dog's testicle
The testicles are paired organs located in the scrotum. In the prenatal period, they develop from germs located on the medial surface of the intrarenal glands. In the later stages of fetal development, the testes move from the inside of the peritoneal cavity to the vaginal process, which is covered by the scrotum (this process is the descent of the testicles).
Interestingly, not all animals have their testicles descended - elephants' testicles are physiologically located in the abdominal cavity. In rodents, the testes descend periodically, during the reproductive period they descend to the scrotum, and after mating ends, they return to the abdominal cavity.
The construction of the kernel is not as simple as it may seem. The organ is covered with a fibrous sac, which is additionally protected by the visceral lamina of the vaginal sheath. Starting from the outside, the nucleus consists of the whitish membrane, the septum of the nucleus (they are derived from the whitish membrane, divide the parenchyma into small pyramid-shaped lobules) and the interonucleus. These elements are made of connective tissue.
The testicular parenchyma consists of the convoluted seminiferous tubules, the straight seminiferous tubules, the testis network and testicular conductors. Each lobe contains two to five spiral coils. The tortuous coils form loops that open into the midnucleus, ending in the nucleus network, but before the exit the coil straightens. There are Leydig cells around the straight coil. Leading conductors (eight to twelve) emerge from the nucleus network and enter the epididymal head, further forming the epididymal duct.
Predisposition in the testicle in the dogPredisposition to cancer
- The main predisposition for testicular cancer is uncastrated males.
- Tumors occur mainly in middle-aged or older dogs (about 7-8 years of age, most often over 10 years of age), but it is possible to develop tumors also in younger animals.
- Particularly predisposed breeds are boxers, German shepherds, Afghan sighthounds, fox terriers, huskies, and Shetland sheepdogs. Interestingly, testicular tumors are rare in dachshunds and rottweilers.
- Dogs with cryptorchidism are particularly predisposed to developing testicular cancer. Research reports that testicles that have not descended into the scrotum are 14 times more likely to develop a neoplastic process in their parenchyma. It has to do with temperature - in the abdominal cavity the temperature is even several degrees higher than in the scrotum, which promotes the development of the neoplastic process. Neoplastic changes in undescended testes develop much earlier and may affect animals as early as 4-5 years of age. Interestingly, neoplastic changes in undescended testes are most often Sertoli cell tumors.
- Infectious agents and the presence of parasites such as leishmania and heartworms are also important. They can also contribute to the development of the neoplastic process.
Testicular tumor in dog, clinical signsTesticular tumor symptoms in a dog
Very often, at the beginning of the development of the neoplastic process, testicular tumors do not show any symptoms. In many dogs, slight neoplastic changes in the testicular parenchyma are not found until necropsy.
Only in the later stages of the development of the neoplastic process do clinical symptoms manifest. Symptoms may vary depending on the hormonal activity of the tumor, but almost always there is a development of testicular asymmetry - one testicle grows larger. The difference in the size of the testicles may be slight or very clearly marked, the tumors may be up to 10 cm in diameter.
Symptoms may also be related to the presence of tumor metastases. They are most often located in the inguinal and sublumbar lymph nodes, and in the case of large lesions, they may cause pain in this area, pressure on nerves, lymphoedema.
When the cancer process affects the testicle located in the abdominal cavity, the outline of the abdominal wall may be enlarged and the surrounding organs may be put under pressure. Abdominal pain appears, difficulty walking, slight lameness may be noticeable. In advanced cases, ascites may develop when the mass of the tumor puts pressure on large blood vessels located in the abdominal cavity.
It is worth mentioning that the appearance of cancerous tumors in the testicles increases the likelihood of:
- perineal hernia,
- prostate diseases,
- tumors from the anal glands.
Sertoli support cell tumors
The support cells are located in the convoluted seminiferous tubules. They are responsible for the production of hormones, but also regulate spermatogenesis, provide nutrients for cells, which then turn into sperm. With their help, sperm is released into the lumen of the tubes.
They also remove cytoplasmic debris left over from the spermatogenesis process, and produce a fluid in which sperm cells are suspended.
Cancer that stems from these cells can be hormonally active. In such cases, inflammation of the prostate, abscess or cyst formation in the parenchyma of the prostate often occurs. The so-called male feminizing syndrome may also develop.
Sertoli's malformed cells can secrete estrogens, which are female sex hormones. In the course of the male feminizing syndrome, there is initially symmetrical alopecia in the groin, weakness and perineum area. The dog does not itch, lick or scratch the area.
The mammary glands and nipples enlarge. There may be milk secretion and galactorrhea in enlarged glands.
The foreskin becomes drooping, limp and may also expand.
Affected male becomes attractive to other, non-neutered males, mating attempts may occur.
Ignoring the problem can lead to endogenous estrogen poisoning and, consequently, bone marrow failure.
Interstitial-Leydig cell tumors
As mentioned above, Leydig cells are located in the interstitial space around the straight vas.
Leydig cells produce steroid hormones (e.g. testosterone). Interestingly, neoplasms originating from these cells are usually benign, but they can grow to impressive sizes - their diameter may be over 10 cm. These tumors differ in consistency and firmness from the rest of the organ flesh, they are compact, hard and well delimited, they can be felt when palpating the testicles.
Germ cell tumors-seminomas
Seminomas are tumors that appear in one or both testicles at the same time. Hyperplasia can be multifocal, which means that there may be several small neoplastic lesions in one testicle.
Interestingly, seminomas are more common in the right testicle than in the left testicle.
Seminomas can cover the entire parenchyma and are not as well delimited as other neoplasms. Tumors very often develop hemorrhages, and the tumors themselves are lardish in consistency and color.
The tumors mentioned above are the most common when it comes to changes in the structure of the testicles, but there are also other types of changes. It happens that the deformation of the testicle turns out to be a fibroma, leiomyoma, chondroma. Metastases of other neoplastic lesions, e.g. lymphomas, sarcomas can also be found in the testes.
An interesting case is teratomas developing in the parenchyma of the testicle.
On the other hand, germ cell carcinomas and gonadoblastomas are rarely diagnosed in dogs.
Treatment of testicular tumor in dog
Castration is the treatment of choice in the case of neoplastic changes within the testicles.
Before surgery, a blood test must be performed, especially if the male has a male feminising syndrome, to make sure there is no bone marrow impairment. With a very low hematocrit, blood transfusion should be considered prior to surgery.
In the case of cysts or inflammation of the prostate, often accompanying neoplastic changes, antibiotic treatment must be initiated before the procedure. The patient should take medication at least 2 weeks before planned castration.
After the castration procedure, the patient should be given special care. Of course, in connection with the procedure performed, you should ensure peaceful conditions for rest for at least 24 hours after the surgery, as well as administer painkillers and use a protective collar to prevent the postoperative wound from being spilled.
It is important that 6 weeks after the procedure, the inguinal and sublumbar lymph nodes (for example by ultrasound) should be checked for neoplastic metastases. Patients with male feminizing syndrome should take preparations supporting bone marrow regeneration. One month after the procedure, a control blood count should be performed.
In the case of disseminated neoplasms, when distant metastases have already occurred, surgery should be combined with chemotherapy. For human testicular tumors, cisplatin or carboplatin are used, and these drugs can also be used in dogs, after a treatment plan has been agreed with an oncologist. Good therapeutic results can also be achieved with radiotherapy, of course combined with surgery.
The prognosis of testicular tumor in dogs
In the case of changes originating in the testicle parenchyma, with an early castration procedure, the prognosis is good. It is very important that during the procedure as long as possible part of the spermatic cord is removed, it reduces the chances of tumor metastases.
If a male feminizing syndrome has occurred, the prognosis is worse. The bone marrow changes regress fully in approximately 20% of castrated patients. Such patients may require additional treatment or blood transfusions, and it may take up to six months to fully recover.
Semenomas and Sertoli cell tumors can metastasize, so after the castration procedure, the dog should be monitored with regular ultrasound examinations (first a month, then every two months and every six months).
The chance of metastasis in these neoplasms is about 10-15%. Metastases are most often observed in the regional lymph nodes (inguinal, sublumbar), as well as in the parenchymal organs, skin and eyeballs.
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