Paediatric Radiology


Case  19 :  
Pediatric Radiology

A single CT image is provided for diagnosis.

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Fig 1.
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Diagnosis

Ectopia cordis


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Discussion

Ectopia cordis or exocardia has a prevalence of 0.079:10,000. It is a rare congenital defect in fusion of the anterior chest wall resulting in an extrathoracic location of the heart, characterized by a primary failure of descent and midline fusion of the lateral body folds. Ectopia cordis may occur as an isolated malformation or it may be associated with a larger category of ventral body wall defects that affect the thorax, abdomen or both.

Four types of ectopia cordis have been described according to the position of the heart;

1) anterior to the sternum (thoracic: 65%),

2) between the thorax and abdomen (thoracoabdominal: 20%),

3) within the abdomen (abdominal: 10%)

4) in the neck (cervical: 5%).

The thoracic and thoracoabdominal types are most common.

The combination of thoracoabdominal ectopia cordis, lower sternal defect, anterior diaphragmatic hernia, midline supraumbilical defect along with pericardial and intracardiac defects constitute the Pentalogy of Cantrel.

Embryologically, the development of the ventral body wall begins after the eighth day of embryonic life. Ventromedial folding of the paired mesodermal layers gives rise to the thoracic/abdominal walls, the sternum (somatic mesoderm), and to the septum transversum of the diaphragm, pericardium and epimyocardium (splanchnic mesoderm) .The heart originally develops in a very cephalad location and reaches its definitive position by the lateral folding and ventral flexing of the embryo at about 16-17 days of development. Complete or incomplete failure of midline fusion by 9th week can result in a variety of disorders ranging from isolated ectopia cordis to complete ventral evisceration.

Ventricular septal defect and Tetralogy of Fallot are the most common intracardiac defects while omphalocele is the most common abdominal wall defect associated with ectopia cordis. While ectopia cordis is generally considered to be an isolated, sporadic malformation, there have been a number of reports linking it to chromosomal abnormalities. Reported karyotypic abnormalities include trisomy 18, turner syndrome.

The prognosis is generally poor and depends on the severity of intracardiac malformations and the presence of associated abnormalities. Most infants are stillborn or die within the first hours or days of life. Attempts at surgical correction have been largely unsuccessful due to the extent of the associated anomalies. Pregnancy termination prior to viability and a nonaggressive management in the third trimester should be considered and discussed with the parents.


References:
1. Khoury MJ, Cordero JF, Rasmussen S: Ectopia cordis, midline defects and chromosome abnormalities: An epidemiologic perspective. Am J Med Genet 30:811-817, 1988.


Dr Muneesh Sharma, Goa