Unusual case of epigastric heteropagus twinning

Heteropagus twins: six cases with systematic review and embryological insights

PURPOSE

Heteropagus twinning (HT) is a rare anomaly. Six new cases along with a systematic review are described.

METHODS

Six cases of HT managed at two tertiary care teaching hospitals over the last 26 years are described. A PubMed search with words: Heteropagus AND/ OR parasitic twins from 2001 to 2021 hit 183 articles. 36 were added from non-PubMed sources. Finally, 120 cases including 114 from 69 articles and 6 new cases were analysed.

RESULTS

Of the new cases, 2/6 had an antenatal diagnosis. Five were males. 4 autosites had omphaloceles. Split notochord and 2 parasites attached to a single autosite were encountered. 5/6 autosites survived. On systematic review, the most frequent variant seen was rachipagus (n = 50) followed by omphalopagus (n = 46). Limbs were reported in 75 cases. Congenital heart disease was seen in 17/120(14.2%) autosites. Omphalocele and meningomyelocele were the most common extracardiac anomalies in autosites. Weight along with the anatomy and position of heteropagus twins was a better determinant of the mode of delivery than weight alone. Mortality was reported in 12 cases.

CONCLUSION

Autosites in HT generally carry a good prognosis, however, final outcome depends mainly on associated major cardiac anomalies. Meticulous antenatal assessment and preoperative planning are of paramount importance.

LEVEL OF EVIDENCE

IV.

Conjoined twins and conjoined triplets: At the heart of the matter

Conjoined triplets are among the rarest of human malformations, as are asymmetric or parasitic conjoined twins. Based on a very modest corpus of recent literature, we applied the embryonic disk model of conjoined twinning to 10 previously reported cases involving asymmetric anatomical multiplications to determine whether they concerned conjoined twins or conjoined triplets. In spite of their phenotypic similarities, we diagnosed four of these cases as conjoined twins and three of them as conjoined triplets. In the remaining three cases, no definite diagnosis could be made, as essential information was lacking from the reports. We conclude that it is not necessarily the expected duplication or triplication of structures that points to the correct diagnosis in these cases, but the number and mutual position of the hearts they presented with. Considering their rarity we stress to thoroughly investigate and describe internal (dys)morphology in novel cases of (asymmetric) conjoined twins and triplets to further unravel their pathogenicity and come to the correct diagnoses.

Conjoined twins: A report of four cases

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Conjoined twins are a subset of monozygotic twin gestation.

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They are classified according to the most prominent site of conjunction.

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Surgical separation of conjoined twins is extremely challenging and high risk.

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Our reported omphalopagus had no associated anomalies.

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The presence of associated malformations is unrelated to the site of union.

Background

Conjoined twin is a rarely seen congenital anomaly associated with significant morbidity and mortality. The most common types of conjoined twins are thoracopagus. Conjoined twins are either symmetrical twins or asymmetrical or heteropagus. This report records the successful separation of 2 cases of asymmetrical twins and one symmetrical twin with fused livers and diaphragm and communicating peritoneal cavities.

Patients and methods

This study amended and strictly followed the ethical guidelines of the Helsinki declaration, our study included 4 case reports on conjoined twins (CT), 2 male and three female patients; 3 of them were parasitic and one was conjoined. We operated upon 2 parasitics and one conjoined. The 1st case died preoperatively.

Results

Four living children is our result.

Conclusion

As connections between the bowel and bone of the parasite and the respective organs in the autosite are often absent, the parasite could be excised easily without any effect on the autosite. We recommend the separation of the parasite and the autosite as early as possible. In many cases, surgery results in the death of one or both of the conjoined twins, particularly if they are joined at the head or share a vital organ. Our separated twins are yet the youngest living separated twins.

Trial registration

ClinicalTrials.gov Identifier: NCT03388684

Thoracic heteropagus conjoined twins associated to an omphalocele: Report of a case and complete review of the literature

Heteropagus twins are an extremely rare event with an incidence of 1-2 million live births that represents, sometimes, a real challenge for paediatric surgeons. The majority of cases have complete or partial duplication of the pelvis and/or lower extremities. Thoracic heteropagus conjoined twins is a rare condition in which a grossly defective foetus (the parasite) is attached to the thorax of the main foetus (the autosite). We describe a case of a parasitic heteropagus attached at the chest wall with a rare presentation of giant exomphalos on the autosite. In this situation, the separation procedure was simple after a well-done anatomic study using X-ray, ultrasonography, magnetic resonance and echocardiogram are performed.

Heteropagus (parasitic) twins: a review

Heteropagus, or "parasitic," twins are asymmetric conjoined twins in which the tissues of a severely defective twin (parasite) are dependent on the cardiovascular system of the other, largely intact twin (autosite) for survival. The estimated incidence of heteropagus twins is approximately 1 per 1 million live births. Isolated case reports comprise most of published work on this rare congenital anomaly. In the past, review articles have focused narrowly on one particular anatomical subtype of parasitic twin and/or on the anatomicopathology observed. Here, we present the epidemiology, proposed pathoembryogenic origins, anatomical abnormalities, management, and outcomes of the wide array of heteropagus twins described in the English language literature.

Thoracopagus parasites in two sets of twins: evidence for the fusion theory

We report two sets of parasitic twins attached in the thoracic region. Exomphalos major in the autosite was present in both cases. While in case 1, the autosite could be salvaged after easier dissection, in case 2, the autosite could not be salvaged due to the presence of the life-threatening anomalies. The presence of a right-angled communication between the gastrointestinal tracts of the autosite and the independent tactile responses of the parasite from that in the autosite supports the 'fusion theory' to explain the fusion of the embryos that could have led to this defect. The presence of the ano-rectal malformation and common bile duct dilatation exclusively in the parasite appears to be the result of the abnormalities in the endodermal-mesodermal interactions, probably due to the relative positioning of the parasite with respect to the autosite.

Umbilical heteropagous twinning: a case report

Heteropagous conjoined twins are rare and umbilical heteropagous conjoined twins are extremely rare. We present a case with umbilical heteropagous conjoined twins and discuss the diagnosis and management. The parasitic component of heteropagous can be separated and treated successfully in the majority of cases.