When a dog’s testicle doesn’t drop into the scrotum, the condition is called cryptorchidism. It’s one of the most common developmental problems in male dogs, and it carries real health risks if left untreated. The biggest concern is cancer: a retained testicle is 9 to 13 times more likely to become cancerous than one that descended normally. Surgery to remove the undescended testicle is the standard treatment and is considered straightforward in most cases.
How and When Testicles Normally Descend
In a developing puppy, both testicles start near the kidneys inside the abdomen. A small ligament gradually shortens and pulls each testicle downward through the inguinal canal (a passage in the groin) and into the scrotum. This process usually finishes by six to eight weeks of age.
The inguinal canal closes around six months. If a testicle hasn’t made it into the scrotum by then, it’s not going to. A vet may flag the issue as early as eight weeks, but the diagnosis is confirmed at six months. One testicle or both can be affected, though having just one retained is far more common. When both are undescended, they’re usually still inside the abdomen.
Where the Testicle Gets Stuck
A retained testicle can end up in one of two places. It may stop partway through the inguinal canal, sitting somewhere in the groin area where a vet can often feel it during a physical exam. Or it may never leave the abdomen at all, remaining deep inside the belly where it can’t be detected by touch. The location matters because it affects both the health risks and the complexity of surgery needed to remove it.
Why Some Dogs Are More Prone
Cryptorchidism runs in families. It’s a moderately heritable trait, roughly 2.7 times more common in small breeds. Pomeranians, Shih Tzus, and Great Danes are among the breeds with documented higher rates. Research has identified a gene called HMGA2 that plays a role: in pigs, a complete deficiency of this gene causes all affected males to be cryptorchid and sterile, and a variant of the same gene is associated with the condition in dogs.
Because the trait is genetic, cryptorchid dogs should not be bred even if they’re technically fertile. Breeding them passes the problem to future generations.
The Cancer Risk Is Significant
This is the main reason vets push for treatment. A testicle that stays inside the body is exposed to higher temperatures than it was designed for, and over time this increases the likelihood of abnormal cell growth. Three separate studies found that cryptorchid dogs have a 9.2 to 13.6 times higher risk of testicular cancer compared to normal dogs. For certain tumor types, the numbers are even more striking: retained testicles face a 23-fold increased risk of one common type and a 16-fold increase for another.
It’s worth noting that researchers still aren’t entirely sure whether cryptorchidism directly causes cancer or whether the same underlying developmental problem that prevents descent also predisposes the tissue to tumors. Either way, the statistical link is strong enough that removal is the clear recommendation.
Other Complications
Cancer isn’t the only concern. A testicle floating freely inside the abdomen can twist on its blood supply, a painful emergency called torsion. Because the testicle is hidden, the signs (sudden abdominal pain, vomiting, lethargy) can be confusing and easy to mistake for other problems.
Retained testicles still produce testosterone. The cells responsible for hormone production appear to tolerate the abnormal position better than the cells that make sperm. So a cryptorchid dog will still display typical male behaviors like urine marking, roaming, and potentially aggression, even though the testicle you can’t see isn’t producing viable sperm. If both testicles are retained, the dog is sterile. If only one is retained, the dog can still father puppies from the normally descended testicle, though with reduced sperm count.
How It’s Diagnosed
For testicles stuck in the groin, diagnosis is simple: your vet feels for them during a routine exam. Abdominal testicles are trickier. If a testicle can’t be felt anywhere, an ultrasound can locate it inside the belly. In cases where it’s unclear whether a dog was previously neutered or is truly cryptorchid (common with rescue dogs of unknown history), a blood test measuring hormone levels can confirm whether testicular tissue is still present in the body.
Surgery: What to Expect
The treatment is surgical removal of the retained testicle. Most vets recommend removing both testicles at the same time, essentially a neuter, to prevent passing the trait on. However, if you have a reason to delay neutering the normal testicle (some large breeds benefit from later neutering for bone and joint development), it’s possible to remove just the retained one first and schedule the second procedure later.
How involved the surgery is depends on where the testicle ended up. A testicle in the groin area requires a relatively simple incision, not much more complex than a standard neuter. An abdominal testicle requires either a traditional abdominal incision or a laparoscopic approach. Laparoscopic surgery uses a small camera and instruments inserted through a single tiny opening near the belly button, allowing the surgeon to locate the testicle, pull it to the surface, and remove it with minimal tissue disruption. This option results in a smaller incision and lower complication rates, though not every veterinary clinic offers it.
Cost varies depending on location and complexity. At low-cost clinics, a standard neuter for a medium-sized dog runs around $150, and the added charge for a cryptorchid testicle may be only $45 to $55 more. At full-service veterinary hospitals, the total can range from $500 to $1,500 or more, particularly if abdominal surgery or laparoscopy is involved.
Recovery After Surgery
Your dog will likely come home the same day, groggy from anesthesia and a bit disoriented. Most dogs perk up within 24 to 48 hours. They’ll go home with anti-inflammatory pain medication, and you’ll need to keep them calm and restrict activity for about 10 to 14 days while the incision heals. An e-collar (the “cone of shame”) prevents licking at the surgical site.
Recovery from a groin-level removal is comparable to a normal neuter. Abdominal surgery takes a bit longer to heal, and your vet may want a follow-up visit to check the incision. Either way, most dogs are back to normal within two weeks.
What Happens If You Don’t Treat It
Leaving a retained testicle in place is a gamble that gets riskier with age. The cancer risk climbs as the dog gets older, and testicular torsion can happen without warning at any point. The retained testicle will continue producing testosterone, so you won’t see behavioral changes associated with neutering. There is no medication or supplement that will cause a retained testicle to descend after the inguinal canal has closed at six months. Surgery is the only option.