Yeungnam Univ J Med.  2021 Jul;38(3):240-244. 10.12701/yujm.2020.00507.

The diagnosis of an imperforate anus in female fetuses

• Kim HM
• Cha HH
• Kim JI
• Seong WJ
• Park SH
• Kim MJ

• KMID: 2518667
• DOI: http://doi.org/10.12701/yujm.2020.00507

Abstract

Imperforate anus is an anomaly caused by a defect in the development of the hindgut during early pregnancy. It is a relatively common congenital malformation and is more common in males. Although there are cases of a solitary imperforate anus, the condition is more commonly found as a part of a wider spectrum of other congenital anomalies. Although urgent reconstructive anorectal surgery is not necessary, immediate evaluation is important and urgent decompressive surgery may be required. Moreover, as there are often other anomalies that can affect management, prenatal diagnosis can help in optimizing perinatal care and prepare parents through prenatal counseling. In the past, imperforate anus was diagnosed by prenatal ultrasonography based on indirect signs such as bowel dilatation or intraluminal calcified meconium. Currently, it is diagnosed by directly checking the perineum with prenatal ultrasonography. Despite advances in ultrasound technology, accurate prenatal diagnosis is impossible in most cases and imperforate anus is detected after birth. Here, we present two cases of imperforate anus in female fetuses that were not diagnosed prenatally.

Keyword

Female fetus; Imperforate anus; Prenatal diagnosis; Ultrasonography

Figure

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  Fig. 1. The images of fetal ultrasonography of case 1. (A) At 30 weeks of gestation, there is an echogenic ring (open arrow) in the hypoechogenic area (solid arrow), suggesting an intact anus with a rather short perineal body (arrowhead). (B) At 35 weeks of gestation, a short perineal body (arrowhead) is revealed, and an echogenic ring (open arrow) indicating the anal mucosa in the hypoechogenic area (solid arrow) is seen.

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  Fig. 2. Postnatal finding of case 1. No anal opening in the original location is present (arrow). A vestibular fistula is accompanied (arrowhead).

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  Fig. 3. The image of fetal ultrasonography of case 2. At 30 weeks of gestation, the perineum is seen, and an intact anus is suspected because of the hyperechogenic ring indicating anal mucosa (open arrow) in normal sphincter muscles (solid arrow), despite the short perineal body (arrowhead). After birth, the baby was diagnosed with a low-type imperforate anus with a vestibular fistula.

Reference

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