Background

The defects of closure of the abdominal wall include a set of parietal malformations. The omphaloceles are the typical forms of these parietal defects. Their frequency is estimated at 1/5000 deliveries. Thanks to advances in ultrasound, the antenatal diagnosis of these malformations is made possible from 11-12 weeks of amenorrhea. The severity of these pathologies is related to their frequent association with chromosomal or malformative Syndrome (Mohsni et al., 2008); may therefore be a sign of chromosomal aberrations.

1 Observation

1.1 Observation 1

Ms. T., 27 years old, is a third gesture, nulliparous and having two early miscarriages. She had consulted for prenatal follow-up of a 3-month pregnancy. The obstetrical examination was normal.

Obstetrical ultrasound showed an active monopetalous pregnancy. Biometrics corresponded to a pregnancy of 12 weeks of amenorrhea. In addition, there was a well-defined round echogenic formation of 13 mm in diameter attached to the anterior abdominal wall (Figure 1) without any other visible malformation, in particular no abnormality of the neck. A fetid karyotype on amniotic fluid, made at 15 weeks of amenorrhea had concluded to a trisomy 21. A medical interruption of the pregnancy had been decided. This was performed with Misoprostol intravaginally at a rate of 1 tablet every 6 hours. The expulsion took place after the 3rd tablet. The foeto-pathological examination confirmed the diagnosis of omphalocele and revealed a wide labiopalatine cleft.

1.2 Observation 2

A 43-year-old patient, tenth gesture ninth para, she had no notable particular antecedents or malformations in the family. She had consulted for excess uterine height at 22 weeks of amenorrhea.

Obstetric ultrasound had shown a single progressive pregnancy. The fetus had a round formation, well limited to 6 cm in diameter with echogenic content and within which we had objectified a small transonic image (digestive structure). The umbilical cord was inserted on the surface of this formation (Figure 2). On the other hand, there was manifest hydramnios and extreme shortness of the long bones (Humerus, Femur). The diagnosis retained was an omphalocele associated with micromelia. A fetal karyotype was performed and concluded to a trisomy 18. Therapeutic interruption of pregnancy was practiced at 24 weeks of amenorrhea with an expulsion of a stillborn 800 grams female. The fetopathological examination concluded that there was a poly malformative syndrome with extreme shortness of the long bones, a giant omphalocele containing slender loops, stomach and left liver (Figure 3) and a diaphragmatic hernia, hypoplasia of the left heart with mitral atresia suggestive of a Cantrell pentalogy.

1.3 Observatin 3

A 39-year-old woman, second gesture, nulliparous and having one early miscarriage with no notable pathological history, pregnant at 15 weeks of amenorrhea, consulted for prenatal follow-up. The obstetrical examination was normal. Ultrasonography had shown an evolutionary monopetalous pregnancy whose biometry is conform to the term with a well-defined rounded formation with echogenic content located in front of the abdomen, as well as cysts of the choroid plexus, clawed hands, and the fetus was totally akinetic (Figure 4).

Biology and serology were normal. An amniocentesis was practiced at 16 weeks of amenorrhea and concluded to a trisomy 18. An interruption of pregnancy had been practiced. The fœtopathological examination concluded it to be a male fetus with a poly malformative syndrome (Figure 5).

2 Discussions

The omphalocele is a central ventral closure defect leading to herniation of the abdominal viscera in the umbilical cord base. Its frequency varies according to the series of 1/2000 to 1/5000 births (Mohsni et al., 2008). Maternal age does not appear to be a risk factor (Boog et al., 1993; Fratelli and Parageorghiou, 2007; Weiner and Goldostein, 2007). Some authors report a higher incidence in male fetuses (Yokoyama and Del Castillo, 2007; Chen, 2007). In our work, two of our patients were over 38 years old and omphaloceles had interested two boys and one girl.

The review of the literature identifies several familial cases whether they are omphalocele recurrences in the same patients (Mohsni et al., 2008) or sporadic familial cases including 8 cases of omphalocele in the same family (Desselle and Herve, 2007). These familial cases of omphalocele suggest the possibility of a genetic origin (Fratelli and Parageorghiou, 2007). This risk of recurrence, although low, justifies genetic counseling both in isolated omphaloceles and associated with a polymalformative syndrome (Chen, 2007). None of our patients had similar cases in the family.

Thanks to the progress of the ultrasound, the antenatal diagnosis of the omphalocele is made possible in the first trimester. This diagnosis is usually easy. The omphalocele is in the form of a neoformation appended to the anterior abdominal wall; its boundaries are clear and distinct from the abdominal contour. Inside this mass existed heterogeneous echoes, intestinal loops or even hypoechogenic images corresponding to the liver as well as many other organs that can be highlighted. At the same time, there is a reduction in abdominal circumference. Moreover, it is easy to find the implantation of the umbilical cord at the level of this neoformation.

Before the 11th week, it is difficult to affirm the parietal defect (Yokoyama and Del Castillo, 2007; Tourne and Chauleur, 2007). However, the presence of echogenic, homogeneous swelling larger than the abdominal diameter would be in favor of the diagnosis rather than a simple delay in intestinal reintegration into the abdominal cavity (Boog et al., 1993; Van Hoorn and Moonen, 2007). In our case the diagnosis of omphalocele was easy, including the case revealed in the first trimester of pregnancy.

The presence of an excess of amniotic fluid must search for an associated congenital malformation. The isolated omphalocele is not accompanied by hydramnios (Boog et al., 1993). In our observations, the only patient who had a hydramnios had an omphalocele associated with a polymalformative syndrome such as cantrell pentalgia.

The omphalocele should be differentiated from a sacrococcygeal teratoma especially in cases of inferior coelosomia. It should not be confused with an allantoic cyst of the umbilical cord, the latter is purely fluid, projecting on the umbilical path, against the abdominal wall is intact.

In front of any omphalocele, a fetal karyotype is systematically performed. Chromosomal abnormalities are consistently found in 20-54% of cases. We did it in the three patients. The chromosomal formulas were constantly pathological (two cases of trisomy 18 and one trisomy 21). This risk of chromosome aberration is increased by advanced maternal age and the coexistence of omphalocele with other congenital malformations (Mohsni et al., 2008). In the literature the chromosomal abnormalities most frequently found are trisomies 13, 18, 21 (Weiner and Goldostein, 2007; Chen, 2007).

The association of omphaloceles with other malformations has also been reported in many series. The most commonly found abnormalities are cardiac abnormalities (intervenricular communication, interauricular communication, and tetralogy of Fallot), abnormalities of the skeleton and limbs (club foot, amelie) and malformations of the nervous system (anencephaly, hydrocephalus, and spina-bifida), renal malformations.

Three syndromes deserve to be individualized:

(1) Cantrell's pentalogy associates a large epigastric omphalocele containing the abdominal viscera, aplasia of the lower part of the sternum, anterior defect in the diaphragm, absence of the anterior pericardium and cardiac malformations.

(2) Lower coelosomia with hypogastric omphalocele with vesico-intestinal fistula and anal imperforation, or bladder exstrophy;

(3) Beckwith-Wiedemann Syndrome: This is an autosomal-transmitted pathology with a risk of recurrence of 27% (Van Hoorn and Moonen, 2007; Mohsni et al., 2008). It is characterized by the triad: Omphalocele, Macroglossia and a gigantism, his ultrasound diagnosis is difficul.

Obstetric management of ompaloceles is conditioned by their isolated nature or associated with chromosomal or malformative abnormalities. Thus in case of polymalformative syndrome or associated chromosomal anomaly, the therapeutic interruption of pregnancy is the rule (Fratelli and Parageorghiou, 2007; Mohsni et al., 2008).

On the other hand, in isolated omphaloceles, continuation of pregnancy is authorized by means of regular antenatal surveillance and delivery in a specialized center with immediate surgical management. Under these conditions, recent studies report a neonatal survival approaching 100% (Fratelli and Parageorghiou, 2007; Yokoyama and Del Castillo, 2007; Chen, 2007). In our work, the demonstration of chromosomal abnormalities and / or other associated malformations justified termination of pregnancy in all cases.

3 Conclusions

Omphalocele is a rare embryopathy: 1/5000 births. Thanks to the ultrasound, the prenatal diagnosis is made possible from 12 weeks of amenorrhea. This diagnosis is usually easy to confirm. Before any omphalocele, a fetal karyotype is systematically performed. Chromosomal aberration is found in 20-54% of cases. Moreover, the search for associated malformations is essential, they reach one in two patients.

The prognosis of omphaloceles is due more to the presence of congenital malformations or chromosomal anomalies associated with its volume. In isolated omphaloceles, neonatal survival is approximately 100% of cases.

Authors’ contributions

R.H: Editing and supervision, read and approved the final manuscript; D.A: participated in the drafting of the observation, read and approved the final manuscript; B.N: participated in the drafting of the discussion, read and approved the final manuscript; A.A.: checking references. All authors read and approved the final manuscript.

Acknowledgments

We thank the anatomopathology department of Ibn El Jazzar Hospital, Kairouan.

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