In this female fetus, the association of an anorectal malformation (high-type) and hydrometrocolpos with ascites and normal bladder with mild kidney pelvic dilation led to the prenatal diagnosis of a persistent cloaca. Kidney pelvic dilation worsened on follow-up (not shown)

Therefore, a midline pelvic cystic mass which does not belong to the bladder in a female fetus must raise suspicion for hydrometrocolpos and lead to searching for additional anomalies in case of a persistent cloaca. Other differentials may include urogenital sinus teratoma.

One should bear in mind that a persistent cloaca encompasses a large spectrum of anomalies. There have been several other forms of cloaca reported in the literature.

Dr Fabrice Cuillier and Dr Marie Balu also contributed to this case.