Diprosopus Tetraophthalmus with Double Outlet Right Ventricle, Congenital Diaphragmatic Hernia, and Duplicated Gall Bladder on Targeted Antenatal Ultrasound with Postnatal Ultrasound and Computed Tomography Correlation
Corresponding Author: Juvaina Puthiyakam, Department of Radiodiagnosis, Government Medical College, Kozhikode, Kerala, India, Phone: +91 9946050257, e-mail: email@example.com
Received on: 21 June 2023; Accepted on: 27 July 2023; Published on: 25 November 2023
Aim: Diprosopus is the rarest form of conjoined twinning, and hence this case is evaluated in detail with multimodality imaging both antenatally and postnatally.
Background: Diprosopus is a Greek word meaning “two faces.” It is also known as craniofacial duplication. These patients will have two faces with a single thorax and abdominopelvic cavity. The number of limbs may vary from 4 to 7. They are frequently associated with other congenital anomalies of the central nervous, gastrointestinal, cardiovascular, and respiratory systems.
Case description: We are presenting a case of 26-year-old primi conceived by intracytoplasmic sperm injection (ICSI). Targeted imaging for fetal anomalies (TIFFA) scan showed complete duplication of facial structures, cerebral hemispheres, the thalami and midbrain, and a large posterior fossa. Other associated anomalies included a hypoplastic left heart with a double outlet right ventricle, a congenital diaphragmatic hernia on the left side, and a duplicated gall bladder. The fetus had a single trunk and abdomen with two upper limbs and two lower limbs. Prenatal fetal magnetic resonance imaging (MRI) confirmed the findings. The poor prognosis was explained to the parents and they decided on medical termination of pregnancy. Postnatal fetal examination and multimodality imaging [X-ray, ultrasonography (USG), and computed tomography (CT)] were performed which correlated with the antenatal diagnosis and helped to understand and delineate the anatomy better.
Conclusion: Detailed prenatal USG imaging helps in identifying most of the anomalies which can be confirmed by fetal MRI. Postnatal CT with the three-dimensional (3D) reconstruction aids in definite diagnosis in selected patients.
Clinical significance: A high index of suspicion is required to diagnose diprosopus in an anomaly scan. Since it is associated with multiple anomalies of other systems, the radiologist/sonologist should thoroughly search for the same. The supplementary use of fetal MRI helps to confirm the diagnosis. Postnatal CT with 3D reconstruction aids in better comprehension of the anomalies.
How to cite this article: Puthiyakam J, S R, Devarajan E, et al. Diprosopus Tetraophthalmus with Double Outlet Right Ventricle, Congenital Diaphragmatic Hernia, and Duplicated Gall Bladder on Targeted Antenatal Ultrasound with Postnatal Ultrasound and Computed Tomography Correlation. Int J Infertil Fetal Med 2023;14(3):148–153.
Source of support: Nil
Conflict of interest: None
Patient consent statement: The author(s) have obtained written informed consent from the patient for publication of the case report details and related images.
Keywords: Antenatal, Case report, Diprosopus, Fetal magnetic resonance imaging, Parapagus, Postnatal computed tomography, Tetraophthalmus, Ultrasound
Diprosopus or craniofacial duplications are the rarest forms of conjoined twins. The reported incidence in various literature is 1,80,000 to 15 million births (0.4% of conjoined twins.1 Due to the rarity of the condition, the exact pathogenesis and genetics behind are yet to be unwound. In this article, we have attempted to understand the anatomical delineations better using fetal magnetic resonance imaging (MRI) and postnatal computed tomography (CT) with three-dimensional (3D) reconstructions.
A 26-year-old primi came to us for a targeted imaging for fetal anomalies (TIFFA) scan. She was married for 7 years and was diagnosed to have primary infertility. The couple decided to proceed with the artificial reproduction technique (ART) and underwent intracytoplasmic sperm injection (ICSI) with transfer of three embryos. The nuchal translucency (NT) and the first anomaly scans were done elsewhere. NT scan done at 12 2/7 weeks gestation revealed a large posterior fossa consistent with developing intracranial anomaly. NT was increased, measuring 5.7 mm with unossified nasal bone. There was also a suspicion of cardiac anomaly. In view of increased NT and multiple other anomalies, chorionic villus sampling was advised to rule out chromosomal abnormalities. Even though the guarded prognosis was explained to the parents, they opted to continue the pregnancy. Early targeted USG was performed at 17 2/7 weeks in which the possibility of craniofacial duplication was raised and the patient was referred to our center for further management. We received the patient at 18 2/7 weeks for a TIFFA scan.
The fetus had duplication of the cerebral hemispheres, thalami, the third and lateral ventricles, and the midbrain (Figs 1A and B). The posterior fossa was large and cystic (Fig 1A) with severe cerebellar hypoplasia pointing to the possibility of Dandy–Walker malformation.
The fetus had two pairs of eyes with their own lens (Fig. 1C). Two eyeballs were laterally placed on either side within their own body orbit. The two median eyeballs were placed together in a single bony orbit with fused sclera medially (Fig. 1D). There was complete duplication of the rest of the facial structures including the nose, mouth, maxilla, and mandible. The maxilla and mandible had soft tissue fusion in the midline (Figs 2A and B). Only two ears were present. The tongues were fused in the posterior aspect with a single oropharynx (Fig. 2C). There was no duplication of neck structures. Nuchal fold thickness was increased, measuring 11 mm.
Thorax and Abdomen
The fetus had a single thorax and abdominopelvic cavity. There was a left-sided congenital diaphragmatic hernia with herniation of the stomach and left lobe of the liver with mild dextroposition of the heart (Figs 3A and B). Fetal situs was normal (situs solitus). Two closely placed gallbladders were present (Fig. 3A). Rest of the intrabdominal solid organs and bowel appeared grossly normal.
Dedicated fetal echocardiography was performed which demonstrated an unbalanced atrioventricular septal defect. There was also a hypoplastic left atrium and left ventricle with atretic mitral valve (Fig. 4A). The cardiac apex was formed by the right ventricle. Both aorta and pulmonary artery were arising from the right ventricle (double outlet right ventricle) (Fig. 4B).
There were two upper limbs and two lower limbs, but polydactyly or limb deformities were absent. Based on USG it was reported as complete diprosopus or craniofacial duplication with associated cardiac and gastrointestinal anomalies and further fetal MRI was performed which helped us in characterizing the intracranial anatomy better. An additional observation from the MRI was the presence of two brain stem structures (Fig. 5). Rest of the findings were consistent with USG findings (Figs 6 and 7). Following this, the parents were counseled about the poor prognosis and they opted for medical termination of pregnancy. Amniocentesis with karyotyping was done as parents could not afford further evaluation like chromosomal microarray or exome sequencing. Vaginal induction was done, and an 18-week live male fetus was delivered which expired in a few minutes. With appropriate consent of the parents, external examination, and imaging of the abortus were performed. Physical examination revealed two faces medially fused to each other with a single thorax and abdomen (Fig. 8). Two upper limbs and two lower limbs were present without any deformities. The karyotyping report was normal (46 XY).
X-ray, USG (neurosonogram and USG abdomen) and CT with 3D reconstruction were performed.
X-ray: Two cranial vaults were present with two sets of facial bones. Cervical and upper thoracic vertebrae were duplicated (Fig. 9).
Neurosonogram showed two pairs of cerebral hemispheres with each having its own lateral ventricles and third ventricle and a large posterior fossa cyst (Fig. 10) with severe cerebellar hypoplasia and duplicated brain stem. USG of the abdomen demonstrated a duplicated gall bladder.
Computed tomography: In the bone window, two pairs of cranial bones were present which were fused in the midline. Maxilla and mandible had soft tissue fusion in the midline (Fig. 11). Brain window findings were consistent with our earlier observations. Cervical and upper thoracic vertebrae were duplicated (Fig. 11). Duplicated gallbladder and left-sided congenital diaphragmatic hernia with herniated stomach and left lobe of the liver were also present.
Hence, the final diagnosis in our case was parapagus diprosopus (complete) tetraophthalmus dibrachialis dipius with multiple anomalies.
Conjoined twins represent a rare form of twinning with a reported incidence of 1:50,000 gestations. However, accounting for the number of stillbirths and in utero deaths, the incidence may go up to 1:2,50,000 births. The pathogenesis of conjoined twins is still debated widely. The two popular proposed theories are the fission and fusion theories. The age-old fission theory suggests the incomplete division of the embryonic disc after day 13. The more accepted recent theory is the Spencer’s theory of fusion. According to this, initially, two separate embryonic discs lie close to each other and float along the outer surface of the yolk sac or share an amniotic cavity and eventually fuse together after day 13. This theory is more favored by the presence of two umbilical cords or umbilical cords with supernumerary vessels especially in dorsal fusion.2,3 Another evolving research lineage particularly in the current scenario of increasing infertility and ART [in vitro fertilization (IVF)/ICSI)] is the concern about multinuclear blastomeres. Currently, only around 15 cases of post-IVF/ICSI conjoined twins are reported in the literature and no extensive studies are available in this lineage.4 Conjoined twinning can either be due to ventral or dorsal fusion. Ventral fusion can be lateral, rostral or caudal, and dorsal fusion can be craniopagus, rachipagus or pygopagus.2 Our case was ventrolateral fusion giving it the name parapagus. Parapagus spectrum can range from dicephalus to diprosopus. The distance between the rostral ends of embryonic disks increases from diprosopus to dicephalus. Parapagus dicephalus has two heads, a single thorax, and abdomen with 4–7 limbs. They may have two hearts or partially split hearts as well as abdominal structures. Parapagus diprosopus has a single head with two faces, a single thorax, and an abdomen with four limbs. They always share a single heart and single abdominal structures.5
Diprosopus is a Greek word meaning ‘two faces.” It is the rarest type of conjoined twins (0.4%) with female predominance (2:1).6 To the best of our knowledge, there are only about 37 reported cases of diprosopus, and hardly any from Southern India. The facial duplication can be partial or complete. The number of eyes can vary from two to four with duplication of the nose and the mouth. Cleft lip and palate are more frequently associated with anomalies.1 Similarly, cranial duplication can also be partial or complete. Central nervous system anomalies such as anencephaly and holoprosencephaly are observed in most of the reported cases. In our patient, there was no cleft lip/palate or anencephaly. Spinal abnormalities include duplicated cervical and upper thoracic spine and spinal defects.7 Multiple anomalies of the cardiovascular, gastrointestinal, genitourinary, and respiratory systems may be observed. Congenital diaphragmatic hernia is one of the common associations. Cardiac defects include VSD, overriding of the aorta, hypoplastic aorta, and dextrocardia. Hypoplastic kidneys and ureters may also be seen.6,8 Embryological explanation for this constellation of findings can be attributed to the close proximity of the anterior prosencephalon, prechordal plate/oropharyngeal membrane, and cardiogenic plate at around day 23–26.9 There is a probability that the disturbance might have occurred in this region at this time. Chromosomal studies are usually reported as normal. The possibility of conjoined twins can be recognized in the first trimester if a single yolk sac and two closely placed fetal poles are seen. Later in the NT scan, there is a fixed relative position of the fetuses in monozygotic monoamniotic conjoined twins.
A high index of suspicion is required to diagnose diprosopus in anomaly scans. Since it is associated with multiple anomalies of other systems, the radiologist /sonologist should thoroughly search for the same. The supplementary use of fetal MRI helps to confirm the diagnosis. Postnatal CT with 3D reconstruction aids in better comprehension of the anomalies.
We are thankful to Dr Riyazudheen. A professor and head of the dept. of pediatrics, KMCT Medical College, Mukkom for describing the clinical details of the abortus.
2. Spencer R. Theoretical and analytical embryology of conjoined twins: part I: embryogenesis. Clin Anat 2000;13(1):36–53. DOI: 10.1002/(SICI)1098-2353(2000)13:1<36::AID-CA5>3.0.CO;2-3
5. Byers CD, Young JR, Connell M. Parapagus dicephalus dibrachius dipus conjoined twin case. Appl Radiol 2018;47(5):29–32.
7. Yang PY, Wu CH, Yeh GP, et al. Prenatal diagnosis of parapagus diprosopus dibrachius dipus twins with spina bifida in the first trimester using two-and three-dimensional ultrasound. Taiwanese J Obstetric Gynecol 2015;54(6):780–783. DOI: 10.1016/j.tjog.2015.10.010
9. Du XZ, Del Bigio MR, Stefanovici C, et al. A case of diprosopus: a rare form of twinning radiology-pathology correlation. Case Rep Perinat Med 2020;9(1). DOI: https://doi.org/10.1515/crpm-2020-2004
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