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Issue Description
During development before birth, the testicles migrate from the abdomen into the scrotum. Normally this is complete by 10 days of age. Cryptorchidism means that one or both of a dog's testicles have not descended into the scrotum. If this does not happen by 8 weeks, the dog is generally diagnosed as cryptorchid, although the testicles may still descend up to 4 months or so.

Although the condition is of course seen only in male dogs, both males and females can carry the gene for cryptorchidism. Heterozygous males and females, and homozygous females, will be physically normal, but can pass the gene on to their offspring. Homozygous males are cryptorchid. Thus cryptorchidism is thought to be a sex-limited autosomal recessive trait.

Most Affected Breeds
This is a fairly common condition, which is seen most often in the Toy and Miniature Poodle, Pomeranian, Yorkshire and Cairn terrier, Dachshund, Chihuahua, Maltese, Boxer, Pekingese, English Bulldog, Miniature Schnauzer, and Shetland Sheepdog.

This condition is rarely associated with pain or other clinical signs, unless a complication develops. In the event of a complication, such as spermatic cord torsion (twisting onto itself), there will signs consistent with sudden and severe abdominal pain. Most often any clinical signs are associated with neoplasia or cancer.

Cryptorchidism is diagnosed by palpation of the scrotum and finding the absence of one or both testicles. The diagnosis is frequently made in the young healthy dog when he is presented to the veterinarian for routine castration. Often the owner is unaware that the problem exists.

Neutering and removal of the retained testicle is recommended as soon as your veterinarian feels it is safe for the dog to undergo surgery. The procedure normally involves making a second surgical approach over or near the retained testicle. If the retained testicle is intra-abdominal, the second incision will be usually be made along the midline of the abdomen. In effect, your dog will undergo two surgical procedures for neutering instead of one.

There are two good reasons for neutering a dog with cryptorchidism. The first is to remove the genetic defect from the breed line. Since cryptorchidism is an inherited defect, dogs with this condition should not be bred. Second, if the retained testicle is left in the body, the chances are increased that the dog will develop a testicular tumor (cancer) in the retained testicle. The risk of developing testicular neoplasia is estimated to be approximately ten times greater in dogs with cryptorchidism than in normal dogs. In fact, 53% of all Sertoli cell tumors and 36% of all seminomas occur in retained testicles. Additionally, 36% of all spermatic cord torsions are found in dogs with cryptorchidism.

The prognosis is excellent for dogs that are diagnosed and undergo surgery early. The surgery is relatively simple and the outcomes are overwhelmingly positive. The prognosis for dogs that develop testicular neoplasia is guarded to poor and depends on the specific type of tumor and the dog's overall health at the time of diagnosis.

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