Male External Genitalia - Pathology

Pathology of external genitalia

Congenital abnormalities of the penis

  • Absence of penis:usually seen only as part of a major whole-body malformation.
  • Micropenis:seen in bulls (malformation of sigmoid flexure). Also some dogs.
  • Persistent penile frenulum:bulls and dogs. Associated with cork screw or deviation of penis.

Congenital abnormalities of the prepuce

  • Absence or agenesis:may be associated with pseudo-hermaphroditism.
  • Absence of preputial orifice:seen in pups.
  • Phimosis:small preputial orifice, penis cannot be extruded from prepuce.
  • Paraphimosis: prepuce can be drawn behind the glans but cannot return after erection).
  • Hypospadias/epispadius:failure of anatomical closure of prepuce and/or urethra.


  • Posthitis:inflammation of prepuce
  • Balanitis:Inflammation of glans penis
  • Balanoposthitis:usual for both to be involved

Dogs:suppuration and/or ulceration due to E. coli, Proteus or Haemophilus spp.
Bulls:IBR virus causes ulceration which may become secondarily infected.
Rams and wethers:occlusion of the urethral appendage as a result of calculi causing a necrotising lesion of the glans ± urethral rupture and subcutaneous leakage of urine.


Multiple luxuriant growths, painful, easily traumatised. Transmissible to females. Spontaneous regression.

Less common in bulls and dogs, low-grade malignancy may ulcerate and haemorrhage.

  • Melanoma:occurs on prepuce and scrotum of grey horses. Often benign.
  • Transmissible venereal tumour:seen in dogs and bitches.
  • Sarcoids:equine prepuce

Male External Genitalia - Pathology Learning Resources
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Information by kind permission of Professor R W Else