Testicular Disorders in Equids: A Case Series.

Overview

• This study reviews 57 cases of testicular disorders in stallions and donkeys, detailing the types of conditions, diagnostic methods, and outcomes to aid veterinarians in managing these diseases effectively.

Background and Importance

• Testicular disorders in equids are varied and can significantly affect the reproductive lifespan of stallions.
• Veterinarians, especially those working on stud farms, must recognize different clinical signs and know the diagnostic options to properly treat these conditions.

Case Series and Types of Disorders

• The study retrospectively analyzed 57 cases involving testicular abnormalities in horses and donkeys.
• Reported conditions included:
  • Neoplasia (Tumors):
    • 3 unilateral and 1 bilateral seminomas (a type of testicular cancer)
    • 2 Sertoli cell tumors
    • 2 Leydig cell tumors
    • 1 malignant mixed sex cord-stromal tumor
  • Developmental Disorders:
    • 6 cases of testicular hypoplasia (underdeveloped testicles) and disorders of sexual development (DSDs)
    • 24 cases of cryptorchidism (undescended testicles), often with compensatory growth of the descended testicle
    • 2 cases of monorchidism (presence of only one testicle), including one with an abdominally retained testis and Leydig cell tumor
  • Degenerative and Other Disorders:
    • Testicular degeneration, possibly linked to anabolic steroid use causing hypogonadism
    • Spermatic cord torsion (twisting of the cord supplying the testicles)
    • Hydroceles (fluid accumulation around the testicle)
    • Periorchitis (inflammation around the testis)
    • Scrotal sarcoid with severe testicular degeneration (a skin tumor affecting the scrotum)
    • Parasitic orchitis and periorchitis associated with specific parasites
    • Infectious epididymitis with orchitis in a donkey (inflammation of epididymis and testis)
    • Ectopic adrenal cortical tissue found within testicular tissue
  • Rarely Observed Conditions:
    • Cystic ectasia of the rete testis (dilated ducts in the testis) in a cryptorchid testis
    • Ischemic necrosis (tissue death due to lack of blood) following failed laparoscopic castration without testicle removal

Clinical Relevance

• The study emphasizes the complexity and variety of testicular disorders in horses and donkeys, many of which might be underdiagnosed until advanced stages.
• Recognizing clinical signs early and using proper diagnostic tools (clinical exam, imaging, histopathology) is crucial for correct diagnosis and treatment planning.
• Histopathological examination—microscopic analysis of tissue samples—is highlighted as a vital but often missing step for definitive diagnosis.

Pathophysiology and Diagnostics

• The paper reviews the underlying mechanisms causing these diseases, such as tumor formation, developmental anomalies, infections, inflammation, and degenerative changes.
• It also covers clinical presentation variations, from subtle signs to severe symptoms impacting fertility or animal health.
• Diagnostic techniques discussed include:
  • Physical examination including scrotal palpation
  • Ultrasonography
  • Endocrine testing when relevant
  • Imaging for retained testicles (cryptorchidism)
  • Histopathology of biopsied or surgically removed tissues

Outcomes and Treatment Implications

• Understanding the wide spectrum of testicular diseases assists veterinarians in prognosis and treatment choices to preserve or improve stallion fertility.
• Some conditions may require surgical intervention (e.g., removal of tumors or cryptorchid testicles), while others need medical management or monitoring.
• Early diagnosis and appropriate treatment can improve longevity of breeding careers and overall animal welfare.

Conclusion

• Equine testicular disorders are diverse, can coexist, and are sometimes clinically silent until advanced.
• Veterinary awareness, thorough diagnostics, including histopathology, are essential for accurate diagnosis and effective management.
• This case series provides valuable insights and reference for veterinary practitioners to better manage these complex reproductive disorders in horses and donkeys.