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225.e2 Cryptorchidism

Cryptorchidism Client Education
Sheet
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HISTORY, CHIEF COMPLAINT
BASIC INFORMATION
referral laboratories’ reference ranges.
• Absence of one or both testes in scrotum in neutered animals. Diagnosis is based on
Definition • Behavior typical of an intact male in an • Human chorionic gonadotropin (hCG)
Failure of one or both testes to descend into animal presumed to have been neutered stimulation test: testicular tissue is present
the scrotum; literally, “hidden testis” (e.g., adopted as an adult) if blood testosterone level 24 hours after
750 IU hCG IV (dog or cat, any body
Synonyms PHYSICAL EXAM FINDINGS weight) is at least twofold higher than
Retained testis(es) or retained testicle(s), • Only one or no testes are palpable within baseline and is > 0.1 ng/mL.
testicular malposition the scrotum. Testes should be easily palpable • Luteinizing hormone (LH) test (Witness
and normally descended by 8 weeks of age. LH): absence of testicular tissue creates a
Epidemiology • Penile examination: in cats, presence of very strong positive test result (elimination
SPECIES, AGE, SEX penile spines indicates circulating androgens, of negative feedback → unregulated secretion
• Intact male dogs and cats most likely of testicular origin. Spines are no of pituitary LH).
• A presumptive diagnosis can be made at 8 longer present within 6 weeks after removal • Exploratory surgery: confirmatory hormone
weeks of age, and a definitive diagnosis can of testosterone source (e.g., castration). testing is preferred to exploratory surgery.
be made by 6 months.
Etiology and Pathophysiology TREATMENT
GENETICS, BREED PREDISPOSITION • Testosterone is responsible for testicular
• Considered to be an autosomal recessive descent in three stages of migration— Treatment Overview
trait; incomplete penetrance and failure of abdominal, inguinal, and scrotal—through Treatment usually involves castration to
mendelian probability suggest a multifactorial the dissolution of the cranial suspensory liga- eliminate undesirable male behavior, prevent
(environmental chemicals and epigenetic) or ment and contraction of the gubernaculum. development of testicular tumors, and address
polygenic mode of inheritance. • Testicular descent in cats is complete at benign prostatic disease.
• Mixed-breed dogs ≈3.9% birth, but the testes can move freely into
• Purebred dogs ≈8.7% (higher in toy and the inguinal canal for up to 6 months. Acute General Treatment
miniature breeds, German shepherd dogs, • Testicular descent in dogs is not completed Castration:
boxers, and Siberian huskies [14%]) until approximately 40 days after birth. • Parainguinal approach for inguinally retained
• Cats (mixed and purebred) ≈1.3% testis(es)
DIAGNOSIS • Abdominal approach for abdominally
RISK FACTORS retained testis(es)
• Familial Diagnostic Overview • Laparoscopic or laparoscopically assisted
• Antiandrogenic drugs used during pregnancy: Diagnosis of cryptorchidism can usually be abdominal approach for abdominally retained
diethylstilbestrol, estradiol cypionate, proges- made by palpation. In cats, identification testis(es)
togens, cimetidine, flutamide, finasteride of spines on the proximal penis indicates
the influence of testosterone. Under unique Chronic Treatment
ASSOCIATED DISORDERS circumstances, hormone testing or exploratory If surgery is not an option, treatment focuses on
• Testicular neoplasia (p. 962): a cryptor- surgery may be required to make a definitive suppression of androgen production to elimi-
chid testis has a 10-fold greater risk of diagnosis. Ultrasonography rarely results in nate male behavior and prostatic hyperplasia.
tumorigenesis. diagnosis. The risk for tumorigenesis in the cryptorchid
• Hyperestrogenism: secondary to Sertoli cell testis in the absence of androgen production is
tumor development from the cryptorchid Differential Diagnosis unknown but likely remains increased.
testis • Monorchidism (unilateral testicular aplasia) • Deslorelin acetate (Suprelorin [Virbac, unavail-
• Testicular torsion • Anorchidism (bilateral testicular aplasia) able in the United States]): gonadotropin-
• Intersex: male pseudohermaphrodite, • Intersex: male pseudohermaphrodite, releasing hormone (GnRH) analog initially
Klinefelter syndrome Klinefelter syndrome stimulates gonadotropin (follicle-stimulating
• Infertility (p. 541): only if bilaterally hormone [FSH] and LH) production and
cryptorchid Initial Database subsequently androgen concentrations; it
• Benign prostatic hyperplasia (BPH) (p. 824): • Palpation: in tense or nervous animals, the then downregulates the pituitary, resulting
if left intact, cryptorchid males are as likely testis(es) may be drawn proximally toward in suppression of FSH, LH, and androgen
to develop prostatic disease as normal, intact the inguinal canal but may be palpable under production. Frequency of treatment is not
males. sedation or general anesthesia. established; it may be required every 6-12
• Examine the feline penis for spines. months or based on behavior recurrence or
Clinical Presentation • Ultrasonography may be useful in evaluating hormone testing.
DISEASE FORMS/SUBTYPES testes retained in the abdomen, although • Anti-GnRH vaccine (Pfizer; unavailable
• Unilateral: one testis retained (the right testis generally only after pathologic hyperplasia in the United States): has been used by
is twice as likely to be retained as the left) has occurred. the section editor (Kutzler) at q 6 months
• Bilateral: both testes retained (less common intervals. Co-administration of a nonsteroidal
than unilateral cryptorchidism) Advanced or Confirmatory Testing antiinflammatory drug is recommended
• Abdominal: testis(es) retained within the In animals when it is suspected but castration at the time of vaccination to minimize
abdomen (usually near the internal inguinal history is unknown: injection-site inflammation.
ring; rarely at the caudal pole of the kidney) • Serum anti-mullerian hormone (AMH): • Anti-testosterone drugs (e.g., leuprolide,
• Inguinal: testis(es) retained within the physiologic levels of AMH are significantly flutamide): costly and dosage, frequency,
inguinal canal (most common, ≈75%) higher in intact or cryptorchid animals than and efficacy are not well established

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