Cryptorchidism (Undescended Testicle) in Dogs: Symptoms, Diagnosis & Treatment

Veterinary Reviewed | Last Updated: March 2026

> Disclaimer: This article is for informational purposes only and does not substitute for professional veterinary advice, diagnosis, or treatment. Always consult a licensed veterinarian regarding your dog's specific health concerns.

---

What Is Cryptorchidism (Undescended Testicle)?

Cryptorchidism is a developmental condition in which one or both testicles fail to descend into the scrotum from the abdomen, where they originally form during fetal development. It is the most common congenital disorder of the reproductive tract in male dogs, affecting an estimated 1–10% of all intact males. The condition poses significant long-term health risks — most notably a dramatically increased chance of testicular cancer — making early detection and treatment essential.

During normal development, a puppy's testicles form near the kidneys inside the abdomen. Guided by a ligament called the gubernaculum and influenced by hormonal signals, the testicles gradually migrate downward through the inguinal canal (a passage in the groin) and into the scrotum. This journey typically completes by the time a puppy is six to eight weeks old, though in some dogs it may take up to six months. When this migration stalls or goes awry, the testicle becomes "retained" — either inside the abdomen (abdominal cryptorchidism) or within the inguinal canal (inguinal cryptorchidism).

Cryptorchidism can be unilateral (one testicle retained, the far more common presentation) or bilateral (both testicles retained, which is relatively rare). The right testicle is retained more frequently than the left, likely due to its longer migration path. A retained testicle is exposed to higher body temperatures than a normally descended testicle in the scrotum, which disrupts normal sperm production and, over time, significantly increases the risk of malignant transformation.

---

Symptoms of Cryptorchidism (Undescended Testicle) in Dogs

Cryptorchidism itself is often asymptomatic in young dogs, which is why veterinary examination is critical. Symptoms become more apparent as the dog matures or if complications develop.

Early Signs

• Absence of one or both testicles in the scrotum — the hallmark finding, typically noticed during a puppy's first veterinary wellness exams between 8 and 16 weeks of age.
• Asymmetric scrotum — the scrotum may appear smaller or flatter on one side if only one testicle has descended.
• Palpable lump in the groin area — if the retained testicle is lodged in the inguinal canal, your veterinarian (or occasionally an observant owner) may feel a small, firm mass in the groin region.

Progressive Symptoms

As the dog ages, especially if the retained testicle undergoes cancerous changes or hormonal imbalances:

• Feminization syndrome — caused by estrogen-secreting Sertoli cell tumors in the retained testicle. Signs include symmetrical hair loss (alopecia), darkening of the skin (hyperpigmentation), enlarged mammary glands (gynecomastia), a pendulous prepuce, and attraction of other male dogs.
• Abdominal swelling or pain — a retained abdominal testicle that develops a tumor can grow significantly, causing visible distension or discomfort.
• Behavioral changes — some cryptorchid dogs display persistent or exaggerated male behaviors (marking, mounting, aggression) despite appearing to have been neutered, because the hidden testicle continues producing testosterone.
• Infertility — bilateral cryptorchid dogs are typically sterile because the elevated body temperature impairs spermatogenesis. Unilateral cryptorchids may have reduced fertility but can still sire puppies via the descended testicle.
• Prostate enlargement — ongoing testosterone production from the retained testicle can contribute to benign prostatic hyperplasia.

Emergency Signs

Seek immediate veterinary care if you observe:

• Sudden, severe abdominal pain — may indicate testicular torsion, where the retained testicle twists on its blood supply. This is a surgical emergency.
• Vomiting, lethargy, and refusal to eat accompanying abdominal pain — signs consistent with torsion or a rapidly growing intra-abdominal mass.
• Pale gums, weakness, or spontaneous bruising/bleeding — in rare cases, estrogen-producing tumors can suppress bone marrow, leading to life-threatening pancytopenia (dangerously low blood cell counts).
• Collapse or acute abdominal distension — could signal internal hemorrhage from a ruptured tumor.

What Causes Cryptorchidism (Undescended Testicle) in Dogs?

Genetics

Cryptorchidism is primarily a hereditary condition with a complex genetic basis. It is widely believed to follow an autosomal recessive inheritance pattern, though polygenic and sex-limited influences are also suspected. A cryptorchid dog should never be bred, as the trait is reliably passed to offspring. Sires and dams of cryptorchid puppies are carriers and should also be considered carefully in breeding programs.

Hormonal Factors

Normal testicular descent depends on precise hormonal signaling, including:

• Müllerian inhibiting substance (MIS) — governs the transabdominal phase of descent.
• Testosterone and dihydrotestosterone — drive the inguinoscrotal phase.
• Insulin-like factor 3 (INSL3) — crucial for gubernacular development and migration.

Anatomical Abnormalities

Structural issues such as a shortened gubernaculum, a narrow inguinal ring, or adhesions within the abdomen can physically prevent the testicle from completing its journey to the scrotum.

Environmental and Developmental Factors

• Low birth weight or prematurity may delay testicular descent.
• In-utero exposure to endocrine-disrupting chemicals (certain pesticides, plasticizers) has been hypothesized as a contributing factor, though definitive evidence in dogs remains limited.
• Maternal stress or illness during pregnancy may theoretically affect fetal hormonal development.

Age Considerations

While descent can occur up to approximately six months of age, most veterinary reproductive specialists agree that if a testicle has not descended by six months, it is very unlikely to do so spontaneously and the dog should be classified as cryptorchid.

---

Breeds Most at Risk

Cryptorchidism occurs across all breeds but is significantly more prevalent in certain lines and breeds, particularly small and toy breeds:

| Higher-Risk Breeds | Notable Predisposition | |---|---| | Yorkshire Terrier | Among the highest reported incidence | | Pomeranian | Very commonly affected | | Toy Poodle & Miniature Poodle | Well-documented predisposition | | Chihuahua | Frequently reported | | Maltese | Elevated risk | | Miniature Schnauzer | Commonly affected | | Dachshund | Moderate-to-high incidence | | Pekingese | Elevated risk | | English Bulldog | Higher incidence, likely multifactorial | | Boxer | Moderate predisposition | | German Shepherd | Reported at higher-than-average rates | | Shetland Sheepdog | Documented predisposition | | Siberian Husky | Moderate predisposition |

The overrepresentation of toy and small breeds likely reflects both the genetic bottleneck of selective breeding and the anatomical challenges of miniaturization. In breeds with heavy linebreeding or popular sire effects, the recessive genes for cryptorchidism can become concentrated in the population.

---

How Cryptorchidism (Undescended Testicle) Is Diagnosed

Step 1: Physical Examination

Diagnosis begins with a thorough manual palpation of the scrotum and inguinal region during a routine veterinary exam. The vet will:

• Confirm the presence or absence of testicles in the scrotum.
• Palpate the inguinal canal and groin for a retained testicle.
• Assess the size of the descended testicle (a solitary descended testicle may be slightly enlarged due to compensatory function).

Step 2: Abdominal Ultrasound

If the retained testicle cannot be palpated externally, abdominal ultrasonography is the primary imaging tool used to locate it. Ultrasound can identify the testicle within the abdomen or deep inguinal region and assess its size and internal structure for signs of neoplasia. Cost: $150–$350.

Step 3: Hormonal Testing (When Needed)

In cases where a dog has been previously castrated (or the owner is unsure) and no testicles are palpable:

• hCG or GnRH stimulation test — a baseline testosterone level is drawn, then the hormone is administered, and a second testosterone level is drawn 1–4 hours later. A significant rise confirms the presence of functional testicular tissue. Cost: $150–$300.
• Anti-Müllerian hormone (AMH) assay — an increasingly used single-sample blood test that can confirm the presence of testicular tissue without the need for stimulation. Cost: $100–$200.

Step 4: Advanced Imaging (Rare Cases)

If ultrasound is inconclusive — particularly in obese dogs or when a very small abdominal testicle is suspected:

• CT scan or MRI may be used to definitively locate the testicle. Cost: $500–$1,500+, typically requiring sedation or anesthesia.

Step 5: Exploratory Surgery / Diagnostic Laparoscopy

In some cases, definitive localization occurs at the time of surgical correction. Laparoscopy offers a minimally invasive way to visualize and remove an abdominal testicle. This is both diagnostic and therapeutic.

---

Treatment Options for Cryptorchidism (Undescended Testicle)

Medical Management

There is no proven medical therapy that reliably induces testicular descent in dogs.

• Hormonal therapy (hCG or GnRH injections) — historically attempted to stimulate descent, these treatments have shown little to no consistent efficacy in dogs and are not recommended by most veterinary reproductive specialists. Even in cases where partial descent occurs, the underlying genetic defect remains, making breeding ethically inadvisable.
• "Watchful waiting" until six months — in very young puppies (under four months), it is reasonable to recheck at subsequent visits before committing to surgery, as late descent occasionally occurs. Beyond six months, intervention should not be delayed.

Surgical Options

Surgery is the gold standard and strongly recommended treatment for cryptorchidism.

Castration (Orchiectomy) — Recommended

Complete removal of both testicles (the retained one and the descended one) is the standard of care. This approach:

• Eliminates the 10–14× increased risk of testicular cancer in the retained testicle.
• Prevents passage of the cryptorchid gene to future generations.
• Resolves testosterone-driven behavioral and prostatic issues.

• Inguinal cryptorchidectomy — a relatively straightforward procedure if the testicle is palpable in the inguinal canal. Similar in complexity to a standard neuter. Recovery: 10–14 days.
• Abdominal cryptorchidectomy (laparotomy) — an abdominal incision is required to locate and remove a testicle retained within the abdomen. This is a more involved surgery with a slightly longer recovery.
• Laparoscopic cryptorchidectomy — a minimally invasive approach using small incisions and a camera. Offers faster recovery, less pain, and smaller scars. Increasingly available at specialty and university veterinary hospitals.

Orchiopexy — Not Recommended

Orchiopexy (surgically relocating the retained testicle into the scrotum) is performed in human medicine but is considered unethical in veterinary medicine because it masks a hereditary defect, potentially allowing the dog to pass the trait to offspring and to be shown or bred under false pretenses. Most veterinary organizations and kennel clubs condemn this practice.

Alternative/Supportive Therapies

• Pain management — post-surgical NSAIDs and, in some cases, opioid analgesics ensure comfort during recovery.
• Elizabethan collar (cone) — prevents licking or chewing at the incision site.
• Cold compresses — can reduce post-operative swelling during the first 24–48 hours.
• Nutraceuticals and supplements — while not a treatment for cryptorchidism itself, omega-3 fatty acids and probiotics may support general recovery and immune health.

At-Home Care

Following surgery:

• Restrict activity for 10–14 days. No running, jumping, or rough play. Leash walks only for bathroom needs.
• Monitor the incision daily for redness, swelling, discharge, or opening of sutures.
• Administer all medications as prescribed, including antibiotics if given and pain relief.
• Keep the area clean and dry — no baths or swimming until cleared by your vet.
• Attend the follow-up appointment (typically 10–14 days post-surgery) for suture removal or incision check.
• Report any concerns promptly — lethargy, vomiting, refusal to eat, or changes at the incision site warrant a call to your vet.

Prognosis & Life Expectancy

The prognosis for cryptorchid dogs that undergo timely surgical correction is excellent. Once both testicles are removed, the dog's life expectancy is the same as any neutered male dog, and the risk of testicular cancer is eliminated entirely.

• Retained testicles are 10 to 14 times more likely to develop cancer compared to normally descended testicles.
• The two most common tumor types in retained testicles are Sertoli cell tumors and seminomas, both of which can be malignant and metastasize.
• Testicular torsion can occur at any time and constitutes a life-threatening emergency.
• Estrogen-secreting tumors can cause fatal bone marrow suppression.

---

Prevention

Screening Recommendations

• All male puppies should have their scrotum palpated at every wellness visit starting at 8 weeks of age.
• A definitive assessment should be made by six months of age. If one or both testicles are absent from the scrotum at this point, the dog should be diagnosed as cryptorchid and surgery should be scheduled.
• Pre-purchase examinations — if acquiring a male puppy, request veterinary confirmation that both testicles are descended or acknowledge the timeline for expected descent.

Breeding Considerations

• Do not breed cryptorchid dogs. This is the single most important preventive measure at a population level.
• Remove carriers from breeding programs. Parents and full siblings of affected dogs are obligate or probable carriers of the genetic trait.
• Responsible breeders should track the incidence of cryptorchidism in their lines and make breeding decisions accordingly.
• Kennel clubs in many countries disqualify cryptorchid dogs from conformation showing, which provides additional incentive for responsible breeding.

Lifestyle Factors

There are no specific lifestyle interventions proven to prevent cryptorchidism, as the condition is overwhelmingly genetic and congenital. However, ensuring pregnant dams are healthy, well-nourished, and not exposed to environmental toxins supports normal fetal development overall.

---

Cost of Treatment

Costs vary significantly based on geographic location, the position of the retained testicle, the surgical approach, and whether complications arise.

| Procedure | Estimated Cost Range | |---|---| | Initial veterinary exam & palpation | $50–$100 | | Abdominal ultrasound | $150–$350 | | Hormonal testing (hCG stim or AMH) | $100–$300 | | Inguinal cryptorchid neuter | $300–$800 | | Abdominal cryptorchid neuter | $500–$1,500 | | Laparoscopic cryptorchid neuter | $1,000–$2,500 | | CT or MRI (if needed) | $500–$1,500+ | | Post-operative medications | $30–$80 | | Follow-up visit | $50–$100 | | Total estimated range | $500–$3,000+ |

Pet insurance may cover a portion of cryptorchid surgery if the policy was purchased before the condition was noted in the pet's medical records. Review your policy's exclusions for congenital and hereditary conditions carefully.

---

Frequently Asked Questions

Can a cryptorchid dog still reproduce?

A dog with unilateral cryptorchidism (one descended testicle) can still produce sperm from the normal testicle and is capable of siring puppies. However, breeding a cryptorchid dog is strongly discouraged because the condition is hereditary. Bilateral cryptorchid dogs are almost always infertile because the elevated body temperature in both retained testicles prevents normal sperm production.

Will the testicle eventually come down on its own?

In most cases, testicular descent is complete by 8–16 weeks of age. Late descent can occasionally occur up to six months. After six months, spontaneous descent is extremely unlikely, and the dog should be classified as cryptorchid.

Is cryptorchidism painful for my dog?

The condition itself is typically painless. However, complications such as testicular torsion (twisting of the retained testicle) cause severe, acute pain and require emergency surgery. Tumors developing in retained testicles may also eventually cause discomfort.

Is cryptorchid surgery more risky than a standard neuter?

Cryptorchid surgery carries slightly higher risk than a routine neuter, particularly when the testicle is located within the abdomen and requires a laparotomy. However, it remains a commonly performed and generally very safe procedure. The risk of complications (infection, hemorrhage, anesthetic reaction) is low in the hands of an experienced veterinarian.

My dog was neutered, but is still showing male behaviors. Could he be cryptorchid?

It is possible that a retained testicle was missed during a previous neuter, though this is uncommon. A testosterone level or anti-Müllerian hormone (AMH) test can determine whether functional testicular tissue remains. If positive, further investigation and surgery to locate and remove the retained testicle are warranted.

At what age should a cryptorchid dog be neutered?

Most veterinarians recommend neutering a cryptorchid dog between 6 and 12 months of age. Delaying beyond this window increases the cumulative cancer risk, particularly as the dog enters middle age. If a retained testicle is discovered in an older dog, surgery should be scheduled promptly regardless of age.

Can cryptorchidism be detected before purchasing a puppy?

If you are acquiring a puppy older than 8–12 weeks, a veterinarian can palpate the scrotum to check for the presence of both testicles. For younger puppies, a recheck at 12–16 weeks and a definitive evaluation at 6 months are recommended. Reputable breeders will disclose if any puppies in a litter are affected.

Is cryptorchidism covered by pet insurance?

Coverage depends on the insurer and the specific policy. Because cryptorchidism is a congenital/hereditary condition, some policies exclude it, while others cover it if the policy was purchased before diagnosis. Always review the fine print and consider enrolling your puppy in a comprehensive plan as early as possible.

---

This article was written for educational purposes. If you suspect your dog may be cryptorchid, schedule an appointment with your veterinarian for a thorough examination and personalized treatment plan.