Centro de Medicina Fetal, Clinica Santa Isabel, Lima, Perú.

 

 

 

Imperforated anus is a relatively common anomaly with a prevalence of around 4 per 10000 births⁽¹⁾.
It is not life threating but it requires a neonatal urgent surgery that originate discomfort  to the parents.
Most cases are postnatally diagnosed. First trimester diagnosis was reported by Taipale et al in 2005 ⁽²⁾.
To our knowledge our case is the second report.  Perlman et al ⁽³⁾ reported a prevalence of 1.2 % in fetus refered for genitourinary abnormalities. They reported the identification of the anal mucosa in the second trimester and they have a sensibility of 50% for imperforated anus.

A 41-year old woman was seen at our unit at 13 weeks of pregnancy for a first trimester screening.
We found a big cystic structure near de cord insertion and an abnormal tubular anechoic structure in the rectal region. The cystic and tubular structures dissapeared at second trimester.
At the second trimester scan both images disappeared.
The diagnosis of high imperforated anus was confirmed and a colostomy to correct the anomaly was performed.
No other abnormalities were found.

Following images and videos show our findings: