Symptoms of Cryptorchidism (Retained Testicles) in Dogs

Dog Breeds

Cryptorchidism in Dogs is often show no visable symptoms and is rarely painful. In fact, many owners are unaware that their dog has the disorder.

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Introduction

Normal male puppies are born with both testicles in the abdominal cavity. The testes normally descend through the inguinal canal and into the scrotum by the time a puppy is 8 weeks old, although it can occur later. Sometimes, one or both testicles do not descend properly. Cryptorchisism is the failure of one or both testicles to descend completely into the scrotum.

Symptoms of Cryptorchidism in Dogs

Cryptorchidism is often asymptomatic and is rarely painful. In fact, many owners are unaware that their dog has the disorder. However, it is quite important to diagnose and treat this condition, because dogs with retained testicles are at an enormously increased risk of developing testicular cancer. Signs of retained testicles that owners may observe include:

• Noticeable absence of one or both testicles in the scrotal sac, either visibly or upon palpation (the dog’s scrotum looks empty and loose)
• Leg-lifting during urination earlier than expected in a supposedly neutered dog
• Exuberant male breeding behavior (mounting, “humping”) in a supposedly neutered dog
• Intense interested in intact females, particularly when they are in season, in a supposedly neutered dog
• Dog-aggression, especially towards intact males, in a supposedly neutered dog
• Successful mating (cryptorchid dogs may be able to impregnate female dogs, depending upon the location of their retained testicle(s))
• Testicular infection
• Testicular tumors
• Acute onset of extreme abdominal pain (from torsion or twisting of the spermatic cord of the retained testes)
• Symmetrical hair loss (alopecia) along the trunk and flanks
• Pendulous preputial sheath
• Darkened (hyperpigmented) external genitalia
• Feminization (from estrogen secreted by Sertoli cell tumors in retained testes)

While signs of cryptorchidism normally are mild or nonexistent, the condition does carry some risks. Retained testicles develop disease at a much higher rate than do normal testicles – including infection and testicular cancer. They also are prone to twisting, or becoming “torsed”, which causes acute-onset of extremely severe abdominal pain. Some cryptorchid dogs can impregnate females, which is usually quite surprising to owners who have had their dog “neutered,” but unbeknownst to them only one testicle was removed. Other cryptorchid dogs may try but be unable to reproduce successfully due to impaired sperm development in the retained testicle. Mature dogs with two retained testicles are usually sterile.

Dogs at Increased Risk

Retained testicles can occur in any male dog of any breed. Purebred toy and miniature breeds seem to be at significantly higher risk, especially Yorkshire Terriers, Toy Poodles and Pomeranians. Some family lines of German Shepherds, Staffordshire Bull Terriers and Boxers also are predisposed. There is thought to be a strong genetic component to this condition. It is much more common for affected dogs to only have one retained testicle (unilateral cryptorchidism) rather than two (bilateral cryptorchidism). Interestingly, the right testis in dogs is retained almost twice as frequently as the left. The reason for this statistical anomaly is not known.

Diagnosis and Tests

Overview and Facts