This document summarizes common veterinary pathologies of the male genital system in horses. It describes conditions affecting the testes such as hypoplasia, degeneration, and orchitis. It also discusses pathologies of the penis and prepuce like phimosis, paraphimosis, and transmissible venereal tumor. Inflammatory conditions of the penis and prepuce called balanoposthitis are also summarized. The document provides an overview of surgical conditions and vascular abnormalities that can occur in the prepuce and penis.

1. Veterinary Pathology of
The Male Genital System

2. • LH – Leydig cells – testosterone –
interstitial space---Leyding cell tumor
• FSH + testosterone – seminiferous tubules
(spermatogonia) – spermatozoa
– Production of structurally abnormal
spermatozoa and ratio N and AN

3. Penis and Prepuce
• Hypoplasia after castration or intersex states
• Supernumery and ectopic penis
• Contraction of ischiocavernosus muscle allow
arterial input to the corpus cavernosum and
sponiosum, but occludes venous drainage
– Rupture of corpus cavernosum causing hemorrhage
– Vascular shunts from corpus cavernosum to the
corpus spongiosum of the penis or peripenile
vasculature
– Rupture of corpus cavernosum in stallion

4. Surgical Condition of Prepuce
• Varicosities of preputal veins in stallion
• Eversion of preputial mucosa
• Phimosis..very small preputial opening
Paraphimosis..penile swelling
• – inability of penile retraction – trauma
(inflammation or paralysis), tranquilizers

5. TVT
• Transmissible venereal tumor
– Uncertain Histogenesis
– Living cells transfer
– Present on Penis and less commonly on
prepuce
– Transferred to bitch by coitus
– Surgically removed
– Complete removal result in recovery

6. Inflammation of the Penis and
prepuce (Balanoposthitis)
• Blanitis
• Posthitis
• Parainfluenza-3, herpes virus,
Corynebacterium renale, Haemophilus
somnus, fungi, mycoplasmas, Ureplasma
diversum, Trypanosoma equiperdum
• Lymphoplasmacytic infiltrations of
preputial mucosa, varying type of exudate,
necrotic mucosa, ulcers
• Squamous cell carcinoma…Horses

7. Testes
• Hypoplasia – cryptorchidism, intersex states,
chronic diseases, malnutrition, chromosomal
anomalies
• Degeneration – disturbed spermatogenesis –
increases followed by decrease in size – ionizing
radiation, cryptorchidal and ectopic testes,
excessive scrotal fat, localized or systemic
infections, general or specific nutritional
deficiencies (vit. A, zinc), torsion of the cord,
infarction, hormonal imbalances

8. Orchitis
• Interstitial – may not be recognized
grossly, microscopically infiltrations
leading to fibrosis – infectious or immune
• Intratubular – solitary or multiple white-
yellow foci – ascending infection
• Necrotizing – Brucellosis and other
infections, trauma, or ischemia –
coagulative necrosis