Cloacal dysgenesis sequence.

Cloacal dysgenesis sequence is a rare congenital malformation seen in 1:50000 to 250000 neonates. It shows a phallus-like structure, smooth perineum, and absence of urethral, vaginal, and anal openings as primary malformations. We report a case of a 4-day-old preterm female neonate. The prenatal ultrasound showed singleton fetus in breech presentation with echogenic bowel, dilated colon, perineal mass, dilated bladder, and fetal hydrops. The complete autopsy revealed smooth perineum without patent urethral, vaginal, and anal openings, and enlarged wrinkled clitoral-like structure. Other anomalies included renal hydronephrosis, hydroureter, megacolon, and urethral agenesis. The chromosomal analysis showed normal female karyotype. These findings are consistent with cloacal dysgenesis sequence, and it results from the defect in cloaca formation during the first 50 days of gestation. It is usually fatal and should be differentiated from other conditions having better prognosis such as fetal obstructive uropathies and persistent cloaca.