Male External Genitalia - Pathology

Pathology of external genitalia

• CONGENITAL ANOMALIES OF PENIS

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

• CONGENITAL ANOMALIES OF THE PREPUCE

1. Absence or agenesis:may be associated with pseudo-hermaphroditism.
2. Absence of preputial orifice:seen in pups.
3. Phimosis:small preputial orifice, penis cannot be extruded from prepuce.

(Paraphimosis - prepuce can be drawn behind the glans but cannot return after erection).

1. Hypospadias/epispadius:failure of anatomical closure of prepuce and/or urethra.

• INFLAMMATION

1. Posthitis:inflammation of prepuce
2. Balanitis:Inflammation of glans penis
3. 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.

• NEOPLASIA

1. Transmissible fibropapilloma:seen in bulls, bovine papillomavirus type 2.

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

1. Squamous cell carcinoma:seen in geldings.

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

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

Information by kind permission of Professor R W Else