CONGENITAL MEGALOURETHRA: Lower Urinary Tract Obstruction With "The Sandwich Sign"

Congenital megalourethra is a rare disorder that causes functional urinary tract obstruction. A multigravida at 16 weeks' gestation referred for an abdominal cyst was found to have a large urinary bladder along with another dilated cystic structure between the fetal legs (sandwich sign), bilateral echogenic kidneys, and anhydramnios, features suggestive of congenital megalourethra. Medical termination of pregnancy was performed. The male abortus was noted to have a massively distended bladder and a dilated penile urethra. Another patient referred in view of suspected bladder outlet obstruction was diagnosed to have a megalourethra on imaging at our center using the sandwich sign. In severe oligohydramnios the "sandwich sign" helps in "ruling in" the diagnosis of megalourethra and ruling out the common differential diagnosis of a posterior urethral valve.