Anomalies of The Urethra

Steven J. Kraus, MD

DIFFERENTIAL DIAGNOSIS

Common

Normal Urethra (Male)
Normal Urethra (Female)
Posterior Urethral Valve (PUV)
Prostatic Utricle
Bladder Sphincter Dyssynergia

Less Common

Cowper Duct Syringocele
Anterior Urethral Valve
Ejaculatory Duct Reflux
Prostatic Reflux
Reflux into Ectopic Ureter
Urethral Stricture
Urethral Trauma

Rare but Important

Megalourethra
Urethral Polyp
Lacuna Magna
Urethral Duplication

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Location of urethral anomaly on VCUG
Symptoms: Infection, hematuria, dysuria, obstructive
Associated bony anomaly, i.e., pubic symphysis diastasis

Helpful Clues for Common Diagnoses

Posterior Urethral Valve (PUV)
- Important treatable cause of urethral obstruction in males
- Prenatal diagnosis in many cases
- Suspect in males born with thick bladder and bilateral hydroureteronephrosis (HUN)
- Type 1: Abnormal migration of mesonephric ducts resulting in abnormal insertion of valvulae colliculi
- Type 2: Considered by most to not represent PUV
- Type 3: Incomplete dissolution of urogenital membrane (near membranous urethra)
- Ultrasound
  - Bladder wall thickening, HUN, ± renal dysplasia, ascites
- Voiding cystourethrogram
  - Dilated posterior urethra to level of valvulae colliculi
  - ± periureteral diverticula
  - Thick bladder wall
  - ± vesicoureteral reflux, intrarenal reflux
- Fetal imaging
  - Bladder may be thick
  - Bladder distended with keyhole configuration at outlet
  - ± HUN, renal dysplasia, cortical thinning, ascites, oligohydramnios
Prostatic Utricle
- Also called utriculus masculinus
- Blind-ending pouch/diverticulum
- From posterior urethra at verumontanum
- Mesodermal remnant of müllerian tubercle
- Associated with hypospadias in males
  - Larger size correlated with more severe hypospadias
- On VCUG, posterior urethral diverticulum
  - Optimally imaged during voiding in steep obliquity
- Incidentally on US, CT, or MR performed for other indication
- In males after repair of imperforate anus
  - Posterior urethral diverticulum vs. residual of rectourethral fistula
Bladder Sphincter Dyssynergia
- Dyscoordination of bladder and urethral sphincter
- Disruption of central nervous system regulation of micturition
- During bladder detrusor contraction, urethral sphincter fails to relax
- On VCUG, results in dilation of posterior urethra to urethral sphincter
- “Spinning top” appearance in females
- Usually due to underlying neurologic condition
  - Spinal cord injury
  - Myelomeningocele

Helpful Clues for Less Common Diagnoses

Cowper Duct Syringocele
- Cystic dilation at end of Cowper duct
- Frequently asymptomatic
- Can present as urinary infection, hematuria, dysuria, obstructive symptoms
- Possible findings on VCUG
  - Lucent defect with mass effect on bulbous urethra at orifice of duct
  - Larger defect → contrast filling of distal Cowper duct
Anterior Urethral Valve
- Most caused by anterior urethral diverticulum
- Diverticulum expands into urethral lumen during voiding, occluding urethral flow
- Variable obstruction, mild to severe
Ejaculatory Duct Reflux
- Reflux into ejaculatory duct during voiding
- Associated with neurogenic bladder
  - Bladder-sphincter dyssynergia, anorectal malformation
  - Associated with variable degree of urethral obstruction
- Multiple episodes of epididymitis
Prostatic Reflux
- Associated with variable degree of urethral obstruction
- “Cloudy” increased density in distribution surrounding prostatic urethra
Reflux into Ectopic Ureter
- Single system, predominantly in males
- Upper pole of duplex kidneys, usually in females
Urethral Stricture
- Post-traumatic, straddle injuries
- Infectious
- Post-repair hypospadias, epispadias
Urethral Trauma
- Type 1, 2, 3, 4, 5A, 5
- Type 3 (tear at urogenital diaphragm) most common

Helpful Clues for Rare Diagnoses

Megalourethra
- Nonobstructive urethral dilation
- Abnormal development of corpus spongiosum, sometimes cavernosa
  - Scaphoid type: Focally abnormal segment spongiosum; association with prune belly
  - Fusiform: Abnormal spongiosum and cavernosa
- Focally or diffusely dilated, no obstruction
Urethral Polyp
- Symptoms of obstruction or hematuria
- Usually solitary, pedunculated, urothelial-lined benign mass from verumontanum
- Mobile filling defect in prostatic urethra
Lacuna Magna
- Dorsal diverticulum roof of fossa navicularis
- Dysuria, end-void gross hematuria, or hematospermia
Urethral Duplication
- Dorsal (epispadiac), ventral (hypospadiac), and “Y” types
- Complete (2 orifices) vs. incomplete
- Epispadiac: Abnormal orifice above glanular meatus
- Hypospadiac: Abnormal orifice below meatus
- Often incidentally discovered
  - Catheterize largest orifice