Cephalothoracopagus janiceps asymmetros twins: Antenatal sonographic diagnosis

September 1, 2017 | Autor: Dinesh Dhiman | Categoria: Pregnancy, Humans, Female, Conjoined Twins, Clinical Sciences, Adult
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Case Report

Cephalothoracopagus Janiceps Asymmetros Twins: Antenatal Sonographic Diagnosis Dinesh Sharma, MD, Anupam Jhobta, MD, J. R. Azad, MD, D. S. Dhiman, MD, Mansa Pandith, MD, Sanjiv Sharma, MD Department of Radiodiagnosis, Indira Gandhi Medical College Shimla, Himachal Pradesh, India-171001 Received 4 July 2010; accepted 24 October 2012

ABSTRACT: Conjoined twins have been the subject of myth and legend since antiquity because of the rarity and peculiarity of their juxtaposition. Fortunately, modern medical technology and concurrent advancements in surgical techniques provide an opportunity for successful separation and hope of a normal independent existence for these unique children. Antenatal sonography allows timely detection of this condition so that further management may be C 2013 Wiley Periodicals, Inc. J Clin Ultraplanned. V sound 00:000–000, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/ jcu.22021

ceps asymmetros twins diagnosed on antenatal sonography (US).

CASE REPORT

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A 24-year-old multigravida presented at 24 weeks’ gestation with abdominal distension and respiratory discomfort. There was no history of twin pregnancy in the family. US examination using a Xario XG color Doppler scanner with a 5-MHz convex probe (Toshiba, Tokyo, Japan) revealed a live fetus with a single brachycephalic head. The cerebellar hemisphere was small and a posterior fossa cyst was present. There was no hydrocephalus (Figure 1). There were two vertebral columns joining at the base of the skull. No spinal dysraphism was seen (Figure 2). A single thorax with two separate hearts was visualized. There were two aortic arches and two descending aortas (Figure 3). The abdomen was single up to the level of the umbilicus, below which it divided into two halves. There was a single umbilical cord. There was no defect in the abdominal wall. There were two urinary bladders (Figure 4). Two pairs of upper and lower limbs were seen and the sex of the conjoined twins was female (Figure 5). Gross hydramnios was present and the single largest amniotic fluid pocket measured 13 cm. There was a single placenta. The gestational age from the femur length was 25 weeks and 6 days. A diagnosis of janiceps asymmetros variant of conjoined twins was made and the pregnancy was terminated. The US findings were confirmed after delivery. The fetuses were both female. There was a single face with a cleft lip. There

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Keywords: conjoined twins; cephalothoracopagus janiceps; sonography; obstetrics

he earliest documented case of conjoined twins were the Biddenden maids born in 1100. They were probably pyopagus and lived for 34 years.1 Conjoined twins are also known as Siamese twins after a pair born in Siam (Thailand). They were xiphopagus and were named Chang and Eng Bunker. They lived for 63 years.2 Reference to conjoined twins dates back to mythology, where Greek and Roman god Janus had two faces.1 Conjoined twinning occurs due to failure of complete separation of a single fertilized ovum between the 13th and 17th day of gestation.3 The conjoined twins are always identical and of the same sex. Females are more commonly affected, with a male/female ratio of 1:4.4 In this article, we present a case of cephalothoracopagus jani-

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Correspondence to: A. Jhobta

SHARMA ET AL

FIGURE 1. Coronal sonogram of the fetal head showing small cerebellar hemisphere and a posterior fossa cyst.

FIGURE 3. Color Doppler sonogram (coronal section) demonstrating two fetal hearts (arrows) in a single thorax.

FIGURE 4. Axial fetal sonogram showing two urinary bladders (arrows).

FIGURE 2. Longitudinal sonogram of the fetus showing two fetal spines (arrows) converging cranially towards a single head.

was fusion of the thorax and abdomen with two pairs of upper and lower limbs (Figures 6 and 7).

DISCUSSION

Conjoined twins are a rare variant of monozygotic twins. The incidence of conjoined twins is 1:50,000–1:200,000 live births.5 They occur in monoamniotic monochorionic pregnancies. Polyhydroamnios is seen in 50% of cases. Conjoined twins are classified according to the major site of the union, to which the suffix -pagus is added, 2

which means fixed. Thoracopagus twins (joined at the thoracic level) are the most common, accounting for 40% of cases, followed by omphalopagus (joined at the abdomen often including the lower thorax), accounting for 32% of cases.6 Other forms are pyopagus (sacral fusion), craniopagus, and parapagus (fused extensively from side to side). Thoracopagus have the highest incidence of cardiac anomalies of up to 90%.7 Cephalothoracopagus is a very rare variant of conjoined twins occurring once in every three million births.8 Such twins are joined at the head and thorax and are also known as janiceps after the Greek god Janus. The janiceps variety of conjoined twins has two types, asymmetros and disymmetros.9 Janiceps disymmetros have two identical, symmetrical faces looking in opposite directions, fronJOURNAL OF CLINICAL ULTRASOUND

CEPHALOTHORACOPAGUS JANICEPS ASYMMETROS TWINS

FIGURE 5. Axial sonogram demonstrating two pairs of lower limbs, along with the female sex of the fetuses (arrows).

FIGURE 7. Photograph showing female fetuses with a single abdomen and thorax and two pairs of upper and lower limbs. The head is also single and flattened with a cleft lip.

FIGURE 6. Radiograph of the abortus confirming the findings of antenatal sonograms.

tally fused cerebra, separate spines, and four limbs each. Janiceps asymmetros or monosymmetros is a variant having a single hypoplastic face that is composed partially from the face of one twin and partially from that of the other twin.8,10 This variant is similar to our case. The antenatal diagnosis of conjoined twins can be made as early as 7 weeks’ gestation by transvaginal sonography.11 Other associated congenital anomalies like anencephaly can be detected on three-dimensional US at 9 weeks’ gestation.12 The precise evaluation of visceral conjunction is possible after 20 weeks’ gestation.13 Antenatal diagnosis allows planning for the type of delivery and also for timely referral to an institution that has obstetric and pediatric surgical facilities. A prenatal diagnosis of shared organs dictates pregnancy termination or possible surgical separation strategies. Generally, before 24 weeks, VOL. 00, NO. 0, MONTH 2013

termination of pregnancy is by vaginal route with or without destructive procedures and, after this, termination by hysterotomy is the preferred choice.14 US is the modality of choice in diagnosing conjoined twins. This condition should be carefully looked for in every case of twin pregnancy.

REFERENCES 1. Browd SR, Goodrich JT, Walker ML. Craniopagus twins. J Neurosurg Pediatr 2008;1:1. 2. Pring-Puang-Geo S. The six Siamese twins [in Thai]. J Int Coll Surg 1963;6:77. 3. Spencer R. Theoretical and analytical embryology of conjoined twins. Part 1: embryogenesis. Clin Anat 2000;13:36. 4. Campbell S, Theile R, Stuart G, et al. Separation of craniopagus joined at the occiput: case report. J Neurosurg 2002;97:983. 5. Hanson JW. Incidence of conjoined twins [letter]. Lancet 1975;306:1257. 6. Spitz L, Kiely EM. Experience in the management of conjoined twins. Br J Surg 2002;89:1188. 7. Nichols BL, Blattner RJ, Rudolph AJ. General clinical management of thoracopagus twins. Birth Defects 1967;3:38. 8. Chen CP, Shih JC, Shih SL, et al. Prenatal diagnosis of cephalothoracopagus janiceps disymmetros

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SHARMA ET AL using three-dimensional power Doppler ultrasound and magnetic resonance imaging. Ultrasound Obstet Gynecol 2003;22:299. 9. Viggiano D, Pirolo L, Cappabianca S, et al. Testing the model of optic chiasm formation in human beings. Brain Res Bull 2002;59:111. 10. Biswas A, Chia D, Wong YC. Three-dimensional sonographic diagnosis of cephalothropagus janiceps twins at 13 weeks. Ultrasound Obstet Gynecol 2001;18:289. 11. Varma SK, Karen WK, Menahem S, et al. First trimester diagnosis of conjoined twins aided by spa-

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tiotemporal image correlation. J Clin Ultrasound 2011;39:527. 12. Shim JY, Joo DH, Won HS, et al. ‘‘Hugging sisters’’: thoracoomphalopagus with anencephaly confirmed by three-dimensional sonography at 9 weeks of gestation. J Clin Ultrasound 2011;39:279. 13. Mahale A, Venugopal A, Kishore MS, et al. Craniopagus: a preoperative assessment. Ind J Radiol Imag 2006;16:783. 14. Hsieh YY, Chang CC, Lee CC, et al. Conjoined twins cephalothoracopagus janiceps monosymmetros: a case report. Arch Gynecol Obstet 1998;261:163.

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