Congenital megalourethra: prenatal diagnosis and postnatal/autopsy findings in 10 cases

Congenital megalourethra is a rare urogenital malformation characterized by dilation and elongation of the penile urethra associated with absence or hypoplasia of the corpora spongiosa and cavernosa. Postnatal complications include voiding and erectile dysfunction as well as renal insufficiency and pulmonary hypoplasia. To date, only a few prenatally diagnosed cases have been reported. We report on 10 cases diagnosed prenatally and their postnatal/autopsy findings.

The study involved retrospective chart review of all cases diagnosed antenatally in three tertiary care centers over 5 years. Antenatal ultrasound images and medical records from obstetrics, genetics, urology and nephrology were reviewed.

Ten fetuses with megalourethra were identified at a median gestational age of 19 (range, 13-24) weeks and all were confirmed postnatally or at autopsy. Three pregnancies were terminated and seven continued. All cases presented with a distended bladder and megalourethra and all cases had normal karyotype. Of seven liveborn babies, one died neonatally of pulmonary hypoplasia. All six infants alive at the time of writing had a dysfunctional urethra and three suffered from impaired or end-stage renal disease. Associated anomalies were found in half of the cases.

Congenital megalourethra is caused by abnormal development or hypoplasia of the penile erectile tissue, secondary to distal urethral obstruction. When the amniotic fluid volume is normal, survival is possible. However, all liveborn infants have voiding and renal dysfunction and sexual dysfunction is expected. Megalourethra should be considered in all male fetuses presenting prenatally with megacystis and detailed fetal ultrasonography should look for an elongated and/or distended phallic structure as well as any associated anomalies.