Cryptic testis and testicular tumors | dougzin

It is now known that testicular inheritance is not easy: it can be passed on through both parents and there are several possible causes. This makes it difficult to reproduce. Additionally, it is a relatively common problem in many breeds.

In the case of an undescended testicle, the advice for years was to castrate early, especially to remove an undescended testicle, also known as an “inner bladder”. This was done because of the increased risk of testicular tumors.
It is known that an undescended testicle is more than 10 times more likely to develop a tumor than a testicle that has completely descended into the scrotum. In addition, the chance of malignancy in the undescended testicle is greater than in the descending testicle, and the tumor in the descending testicle is usually benign.
The question is, of course, whether this greater chance is really a good reason to castrate a male at an early age. Because in the case of an occult testicle, castration at such a young age is actually a preventive castration and in the case of an undescended testicle, it is often already done at 5-6 months. Is that wise? What are its advantages and disadvantages?

How often does it happen?

To find out how often undescended testicles occur, we look at groups of purebred dogs. This gives a good picture because the relationship between the animals is recorded there and percentages can actually be determined within these populations. These studies show that the incidence varies widely, from 1% to about 11% to be exact. In about 75% of cases, there is a unilateralism, something commonly referred to as monorchidism in purebred dog breeding. In those single-breed dogs, 30-40% appear to have a testicle in the abdominal cavity, and in the remaining animals the testicle is in the inguinal canal.

It is normal for the testicles to descend between 6 and 16 weeks of age. This difference in lifespan is due to the fact that it can vary greatly for each breed. If the testicles haven’t fully descended by 16 weeks of age, don’t panic: Until about 10 months, descent can occur completely naturally.


Testicular tumors are common. Not just with cryptic animals, but with all males. The percentage is about 25%. In almost all cases, the tumor remains where it is located: in the testicle. Then the prognosis is excellent: the testicle has disappeared, the tumor is gone.
But in about 15% of cases, metastasis occurs in the lymph nodes, liver or lungs. In practice, this is a very small percentage: 15% out of 25% equates to about 3.5% of males. So all males. Thus the chance of a cryptic male developing a malignant tumor that is also metastasized is the same as that of a full male. And this chance is small.

If a tumor develops in the undescended testicle, it is usually either a seminoma or a Sertoli cell tumor. The most malignant form is also the rarest: about 8% of cases. Of these 8%, about 10% also develop metastases, but this only occurs in older males. The age limit is about 10 years

feminine features

These two types of benign tumors sometimes cause a hormonal imbalance, leading to an excess of estrogen. Characteristics known as feminizing syndrome can develop: a male develops feminine characteristics and may develop a number of characteristics resulting from a hormonal imbalance.
It relates to a series of symptoms, such as symmetrical baldness, poor coat quality, thin skin, black (discoloration) of the skin, enlarged nipples and development of the mammary glands, reduction in the size of the penis and healthy testicle, and reduction or enlargement of the prostate. The male can get a smell like a bitch, which can make him suddenly interested in other males. Finally, anemia can also occur.

In many cases, this anemia can be reversed, especially if it occurred after the tumor and testicle were removed, but unfortunately this problem is not always reversible. If so, the prognosis is unfortunately poor.

Testicular torsion

The above are options for tumors that can occur in healthy males, as it really makes no difference whether a male has cryptorchidism or not. If he did, something else could go wrong: Testicular torsion might occur. This rarely happens. In the case of torsion, the testicle rotates around its axis and the blood vessels narrow, so that this is a very severe and painful condition that can only be treated surgically.

The prognosis for testicular tumors in cryptic animals is very good. Anyone who still feels uncomfortable with the idea of ​​an invisible testicle somewhere can opt for a regular ultrasound. In this way, any problem will be caught in time.

All of the above scenarios are rare and are no more common in non-cryptorchid males or monotestes than in males with undescended testicles. This means that there is no medical reason to neuter such dogs, and certainly not to do so before the age of one year. It is also important to consider that castration often has negative effects.

effects of castration

Fortunately, in the Netherlands and Belgium there are many healthy males. There is an increased tendency to castrate only if there is a (medical) need for it. With healthy animals, both dog and owner don’t seem to have insurmountable problems with that healthy condition.

Neutering an animal with undescended testicles, as described above, is not medically necessary.
Studies show that male monorchids that have not been neutered live as long as healthy males that have testicles. Therefore, monorchid does not pose any additional risks.
Also, early castration (less than one year old) is not justified on medical grounds, at least not when it comes to preventing the development of malignancy.

Aside from monorchidism, there may be other reasons for castration, but it is always important to ask yourself if castration will solve the problem. This is by no means always the case.

trial period

For example, castration is not always the answer to behavioral problems. There may of course be a serious problem, such as aggressiveness, constant escapism that endangers one’s life or uncontrollable hypersexuality with possible loss of appetite and its consequences.
In such cases, it is important to check first by ‘trial castration’ whether the castration will actually have the desired effect. This can be done using what is called a castration slide, also known as a ‘chemical castration’. The advice is not to wait too long with such a trial period, because the behavior often turns into a habit, and then the actual castration will have no or insufficient effect.
In the case of aggression, it is important to properly direct the dog, possibly with the help of a behavioral therapist. In these cases, castration chip is not always successful, and therefore castration is not.

There may also be practical reasons for castration. For example, when a male is not being used for reproduction and is living with healthy females, castration can be a practical solution. Castration can also offer a solution for overly discerning males, which is more common in certain breeds than others. Service dogs are also often neutered so that their hormones do not interfere with the work they are supposed to do. And while this is not true of our environment, it remains important to recognize that there are areas where stray animals are a major nuisance and where castration is a better option than surplus, resulting in the mass euthanasia of animals.

If there is testicular torsion, a tumor, or prostate problems, a little discussion is needed: then castration Always for the benefit of the animal.

It cannot be reversed

All this does not change the fact that castration is not innocent. It can have far-reaching consequences that cannot be reversed with a final castration. Missing hormones can cause socially insecure behavior that leads to fear (aggressiveness). Weight problems can arise because the metabolism has become slower. Coat problems are a structural problem, especially in shedding breeds: there is consistent shedding and a different hair structure. Neutering makes many dogs less interested in the environment and therefore lazy. Castrated males have an increased risk of prostate cancer, Cushing’s disease, diabetes, and hypothyroidism. Of course, there are exceptions where the dog does not suffer from any problems. It is important to realize that this is a minority.


Breeders in particular have difficulty with crypt testis and this is mainly because we cannot get a picture of the mode of inheritance. It’s not clear why testicles sometimes fail to descend, and although there’s a familial connection – the problem is clearly more common in some breeds than others – we can’t eradicate the problem.
This also applies to more animals, dogs are not unique in this. And in all of those animals, the genetic component is evident, but not traceable. This may be due to the fact that there can be several reasons. The opening in the inguinal canal may be very narrow, but it may also be due to the tendon connection between the testicle and the scrotum, which, as it were, pulls the testicle down. Sometimes this does not happen, and is it because of the tendon? Or for something else? It is simply unknown.

What we do know is that selection has little effect: sufferers have been excluded for a long time yet cryptic pups are still born. Heredity likely lies in many genes, there may be several causes, and finally, bitches do not have testicles, but they can carry genes that contribute to the testicles. But of course this is not visible in a bitch.
This makes cryptorchidism one of the most difficult problems in reproduction: nearly impossible to eradicate without excluding entire populations.

But although the loss of a testicle is undesirable, the health risks with such a male are fortunately no greater than with a full male.
This also applies to the fertility of these males: although a dog in which neither testicle has descended is always sterile, this is certainly not the case with a dog with one testicle. It is as virile as a dog with testicles and can also produce offspring. This makes him at most a dog with an external defect, but who otherwise has all the qualities of a normal male

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