Prenatal Rupture of Hydrocolpos in a Cloacal Malformation.

INTRODUCTION: Cloacal dysgenesis occurs from failure of embryological division of urogenital sinus and hindgut, leading to a single common perineal opening for genitourinary and gastrointestinal tracts. The prenatal diagnosis of cloacal malformation is imprecise, but the clinical correlation of postnatal findings to prenatal history can help reveal explanations for unusual pathological findings in patients with urogenital abnormalities. CASE PRESENTATION: A 21-year-old woman was referred after her 20-week ultrasound demonstrated anhydramnios and concern for dilated fetal bowel. Fetal MRI confirmed anhydramnios and a dilated fetal colon, in addition to hydronephrosis and a pelvic cyst. Repeat ultrasound at 27 weeks showed unexpected complete resolution of her anhydramnios but new fetal ascites. The newborn girl was postnatally diagnosed with a cloacal malformation and an unusual near-complete fusion of her labia. She underwent proximal sigmoid colostomy and a tube vaginostomy at birth followed by cloacal reconstruction at 1.5 years old. CONCLUSION: In female fetus with a pelvic cyst, one should have a high index of suspicion for cloacal anomaly and consider the possibility of urinary obstruction leading to alteration in amniotic fluid.