Introduction

• Cause: heritable failure of normal testicular descent.
• Incidence: 1-15% of males.
• Signs: may be none except absence of testicles in scrotum, or signs related to secondary complications of retention.
• Diagnosis: imaging or indentification at laparotomy.
• Treatment: bilateral orchidectomy.
• Prognosis: significantly increased risk of testicular neoplasia, (particularly Sertoli cell tumors).
• If intra-abdominal, increased risk of testicular torsion.
  Print off the owner factsheet Cryptorchidism in the dog (retained testicle) to give to your client.

Pathogenesis

Etiology

• Heritable - possibly autosomal recessive gene.
• Absent or aberrant gubernacular growth leads to failure of testicular descent.

Pathophysiology

• Sex-linked, autosomal recessive gene.

• Long-term exposure to normal body temperatures →
  • Degeneration of germinal epithelium and exocrine function.
  • Interstitial and sertoli cells remain functional so endocrine function is nearly normal.

Possible anomalies

• a) Reversed outgrowth of gubernaculum into abdominal cavity instead of inguinal canal, no testicular migration, remains in high abdominal position.
• b) Mixed intra-abdominal and inguinal outgrowth, some abdominal migration, testicle closer to inguinal canal.
• c) Increasing extra-abdominal growth, inguinal or parapenile testicle (more common).
• Right:Left ratio - 1.8:1.
• Bilateral/unilateral (more common).
• Significantly increased risk of testicular neoplasia (especially Sertoli cell) in both testes, even descended one (if unilateral).
• Intra-abdominal testicular torsion possible .

Timecourse

• Testicular neoplasia occurs at a younger age in cryptorchid testes when compared to scrotal testes.

Diagnosis

Treatment

Prevention

Outcomes