Antenatal ultrasonographic appearance of isolated fetal ascites. A case report of sinus urogenitalis.

BACKGROUND

Isolated fetal ascites can be caused by many heterogeneous disorders and is associated with a variety of conditions. Cloacal anomalies are rare abnormalities with a highly variable array of sonographic symptoms, which make them difficult to diagnose antenatally. We present a case with isolated fetal ascites without hydronephrosis caused by a cloacal malformation.

CASE

A 28-year-old woman, gravida 2, para 1, was referred to our unit at 18 weeks gestation with a hyperdense structure in the fetal liver. Cordocentesis revealed a normal karyotype and negative viral titers. Isolated fetal ascites occurred for the first time at 23 weeks gestation. Serial ultrasounds showed progressive fetal ascites with no hydronephrosis at any time and no other malformations apart from the previously diagnosed hyperechogenic liver structure. After the insertion of an abdomino-amniotic shunt, a temporary reduction of the sonographically detectable ascites could be achieved. Cesarean delivery was necessary due to a pathological CTG at 33 weeks of gestation. The baby was born with a markedly distended abdomen. Postnatal radiologic examination showed two fistulae between the cloaca and the notedly dilated vagina and the rectum respectively. At the age of 3 months a vaginoplasty was performed, which involved creating a correctly positioned vaginal opening, reconstruction of the urethra and rectum as well as occlusion of the two fistulae.

CONCLUSION

In view of the examinations, performed before and after delivery, it has to be assumed that fetal urine drained via the cloaca through the fallopian tubes into the abdomen. In contrast to usual appearance of cloacal malformations no hydronephrosis was detected and the kidney function was normal at all times. To our knowledge, this is the first published case of isolated fetal ascites without hydronephrosis caused by a cloacal malformation.