FETAL HYDROMETROCOLPOS, UTERUS DIDELPHYS WITH LOW VAGINAL AND ANAL ATRESIA: DIFFICULTIES IN DIFFERENTIATION FROM A COMPLEX CLOACAL MALFORMATION: A CASE REPORT

Summary: Fetal hydrometrocolpos, uterus didelphys with low vaginal and anal atresia: difficulties in differentiation from a complex cloacal malformation: a case report: Hydrometrocolpos, occurring in approximately 1/6000 newborn girls, can be caused by a stenotic urogenital sinus, a severe cloacal malformation, but also by other conditions such as an imperforate hymen, a midline vaginal septum and vaginal atresia. The prenatal differential diagnosis of this wide spectrum of conditions is not easy and requires a multidisciplinary approach with follow-up scans and MRI to access the severity of the condition.A non-consanguineous couple was referred in the first pregnancy at 30 weeks. The father, 30 years of age, of Kaukasian origin, and the mother of Asian origin, 26 years of age. Ultrasound at 30 weeks revealed ambiguous genitalia (with suspicion of clitoral hypertrophy), a septated structure located behind the bladder compatible with hydrometrocolpos with a uterine malformation (uterus didelphys), a single umbilical artery, mild ascites and growth on the tenth centile. The differential diagnosis included a vaginal atresia, a urogenital sinus and a more severe cloacal malformation. After serial scans, MRI and counselling by an experienced surgeon the preferential diagnosis of a cloacal malformation was made and a late pregnancy termination was performed. Pathological examination revealed :low vaginal atresia with uterus didelphys, anal atresia with rectovaginal fistula and a normal urinary tractus.The differential diagnosis between hydrometrocolpos due to vaginal atresia or due to a more severe cloacal malformation is not straightforward. Care should be taken in decision making and counselling patients with these complex prenatal malformations.Key-words: Multiple congenital anomalies - Fetal malformation - Anogenital anomaliesINTRODUCTIONThis report describes a third trimester diagnosis of hydrometrocolpos due to a low vaginal atresia with anal atresia and the difficulty in differentiation from a complex cloacal dysgenesis.CASE REPORTThe couple, without medical history, was referred at 30 weeks gestation by the local gynecologist with the ultrasound diagnosis of a single umbilical artery in their first pregnancy. Follow-up examinations in the first and second trimesters of pregnancy occurred abroad.Ultrasound at 30 weeks revealed ambiguous genitalia (with suspicion of clitoral hypertrophy), a septated structure located behind the bladder compatible with a uterine malformation, a single umbilical artery, mild ascites and growth on the tenth centile (Fig. 1).To differentiate between a vaginal atresia, a urogenital sinus malformation and a more severe cloacal malformation additionally an MRI scan was performed confirming the septated structure posteriorly from the bladder suspicious of a hydrometrocolpos, the ascites likely due to intraabdominal spil, meconium filling of the rectum but possible anorectal atresia and the other ultrasonografically described malformations (Figs 2-3).After referral to a tertiary center the likely diagnosis of a cloacal dysgenesis was made and the couple was councelled abroad by an experienced surgeon in the field of cloacal anomalies. Due to the infaust prognosis given by the surgeon the couple had a third trimester pregnancy termination in another center.Pathological examination revealed : a female fetus (weight 1900 g, length 43 cm, head circumference 30 cm) with a single umbilical artery, a low vaginal atresia with doubled vagina, uterus didelphys and secondary hydrometrocolpos and due to the pressure of the hydrometrocolpos a mild hydronephrosis with otherwise normal urinary tract. Additionally an anal atresia with rectovaginal fistula was present.DISCUSSIONA cloacal malformation is not common with an estimated incidence of 1/50000 births.Typically in cloacal malformation there is a common opening for the urinary, genital and gastrointestinal tract. …