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

Monosymmetros Cephalothoracopagus Tetrabrachius and Tetrapus Piglets with Syndromic Evolution

Conjoined twins are rare congenital malformations that have been reported in mammals. Two different cases are presented in this study. Case No. 1 features monocephalic, thoracopagus-conjoined twin piglets with anencephaly and palatoschisis of the Pietrain breed, and case No. 2 features monocephalic, thoracopagus conjoined twin piglets with palatoschisis and bifid root tongue of a mixed breed. These cases were examined using post-mortem and computed tomography (CT) examinations. In both cases, the conjoined symmetrical twins had a single head, one neck, and fused thoracic cavities, while the abdominal cavities were separated. Similarly, in both cases, they had four forelimbs and four hindlimbs and duplicated foramen magnum. During CT examination, in case No. 1, severe abnormalities were observed in the skull and vertebral column. In the left twin, occult dysraphism was seen from the C2 vertebra until the end of the vertebral column, and in the right twin, from the C3 vertebra until the end of the state vertebral level. In case No. 2, the oral cavity contained a tongue with a bifid root connected with one hyoid bone, and the soft palate presented a small cleft. During CT examination, the parietal bone and the occipital bones were partially duplicated. This case also presented occult dysraphism, but only in the cervical vertebrae, C1-C6 for the left twin and C1-C5 for the right twin. In both cases, abnormalities of the internal organs were revealed during necropsy. Conjoined twins with multiple congenital anomalies presented here enhance our understanding of the various clinical forms of conjoined cases in veterinary medicine.

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.