Prenatal diagnosis of a prolapsed ureterocele with magnetic resonance imaging.

Ectopic ureterocele with ureteral duplication is the most common type of ureterocele found in children. Early accurate diagnosis is desirable to decrease the risk of urosepsis and renal damage. Prenatal imaging with ultrasonography detects the vast majority of ureteroceles; however, in some cases, the diagnosis may remain in doubt. We report on the use of magnetic resonance imaging to clarify the prenatal diagnosis of a prolapsed ureterocele.