Agnathia‐otocephaly with holoprosencephaly on prenatal three‐dimensional ultrasound
AbstractOtocephaly—also called agnathia-otocephaly or agnathia-microstomia-synothia—is an extremely rare lethal anomaly. Since its first description by Kerckring in 17171, more than 140 affected individuals have been reported2, 3. This sporadic abnormality is characterized by an absent or hypoplastic mandible, a small or absent mouth (microstomia) and a midfacial location of the ears in the form of auricular malposition called melotia and/or auricular fusion called synotia3. Otocephaly occurs commonly in association with severe midline defects including holoprosencephaly, cyclopia, proboscis and other cerebral malformations. It has been reported to occur in fewer than 1 in 70 000 births2, 3. However, Blaas et al.4 found 10% of all holoprosencephalies in their series to have otocephaly and suggested that the true incidence is underestimated. We would like to contribute to the literature with a description of an additional extreme case detected at 21 weeks' gestation, and emphasize the role of three-dimensional (3D) ultrasound in demonstrating the facial features. The patient (gravida 2, para 1) was referred after a second-trimester ultrasound scan had raised suspicion of a severe malformation of the fetal brain and face, while the facial features could not be properly evaluated. Nuchal translucency was not measured at 11–14 weeks' gestation. The fetus showed typical features of alobar holoprosencephaly, with a round-shaped head and microcephaly (biparietal diameter 42 mm, head circumference 145 mm; < 3rd centile). On two-dimensional (2D) ultrasound the face showed the presence of one centrally located eye, identified as cyclopia without proboscis (Figures 1 and 2), no nose, no mouth orifice and no mandible. An attempt to obtain a midsagittal view did not show any signs of a recognizable fetal profile (Figure 2). Only in a coronal oblique view could it be demonstrated that the ears were positioned near the midline, identified as synotia (Figure 3), allowing the diagnosis of agnathia-otocephaly with holoprosencephaly and cyclopia. The heart and abdominal situs were normal and no additional malformations were found. The stomach was nearly empty and amniotic fluid was slightly increased. There was a velamentous insertion of the umbilical cord. The patient wished to understand the facial anomaly, and 3D ultrasound with surface rendering permitted visualization of the face, as shown in Figure 4 and Videoclip S1 (Voluson 730 Expert, 3D-rendering with 4–8-MHz transducer and 4DView 10.0® Software, GE-Medical Systems, Zipf, Austria). Surface rendering showed clearly the cyclopia and the synotia as the only facial features present. Maximum mode rendering confirmed the closure of the metopic suture in alobar holoprosencephaly, as previously described5. Ultrasound image (transverse view) showing the round-shaped head and the single eye identified as cyclopia. Midsagittal view of the face showing the eye situated in the middle of the face and absence of the nose, chin, mouth and lips. Coronal oblique view of the face demonstrating the single eye identified as cyclopia and the ears (arrows) near the midline identified as synotia. Visualization of the face using three-dimensional ultrasonography with surface rendering, demonstrating the complete picture of the anomaly with the single eye in the middle of the face, absence of the nose and mouth and fusion of the ears in the midline. Amniocentesis revealed a normal male karyotype. Following counseling, the parents opted for termination of pregnancy. Autopsy of the 350-g male fetus confirmed the ultrasound findings (Figure 5) and also showed absence of the left kidney and small adrenal glands. Lateral to the ear anlage on the left side a very small connection was found into the rudimentary mouth cavity connecting with the esophagus. Postmortem image showing the unusual malformation of the face identified as agnathia-otocephaly with cyclopia, correlating precisely with the prenatal three-dimensional image. Two years later the patient gave birth to a healthy child. The etiology of this complex anomaly is unknown and most reports are sporadic. Anecdotal reports of autosomal recessive inheritance and on the role of drugs have been published2, 3, 6, 7. Interestingly, despite being commonly associated with holoprosencephaly and other typical midface anomalies, otocephaly has not been reported to be associated with trisomy 13, which suggests that it could be a separate brain–face abnormality4, 8. Agnathia-otocephaly is considered to be the most severe form of first branchial arch malformation. It is assumed that failed mesenchymal migration of the maxillary prominence and atrophy in the development of the mandibular prominences are responsible for this severe malformation. The embryologic development of the face occurs at between 4 and 8 weeks postconception. It has been proposed that otocephaly is a result of a severe manifestation of a field defect of the branchial arch components, with disruption of the normally coordinated temporal and spatial unit of the first branchial arch and prosencephalon around the fifth embryological week1, 3, 6. A defect of migration of neural crest cells to the ventral portion of the first branchial arch during gastrulation leads to mandibular aplasia, which then results in a range of associated findings such as ventromedial displacement of the external ear structures (synotia), absence of the tongue (aglossia) and small oral aperture (microstomia). The case we report here is an extreme form of agnathia-otocephaly, showing cyclopia, no nose, no mouth and fused ears in the midline, in addition to holoprosencephaly. The spectrum of disease is, however, wide, as described in extensive literature reviews2, 3, 9, and it has been suggested that the term ‘dysgnathia complex’ be used to describe this spectrum9. Cases with agnathia-otocephaly have in common the underdevelopment or absence of the mandible (hypo- or agnathia), a small or absent mouth orifice (microstomia) and some degree of displacement of the ears towards the midline (melotia, synotia). Underdevelopment and severe malformation of the lower face can be isolated10, but is often combined with facial, cranial and extracranial malformation2, 3. The upper face is often affected, in approximately half of the cases, even with the absence of severe brain malformations, with abnormalities including cyclopia, synophthalmia, proboscis, hypotelorism or uni-/bilateral micropthalmia/anopthalmia and nasal malformations2, 3. Combination with skeletal, genitourinary and cardiovascular anomalies has been reported in many fetuses with agnathia-otocephaly complex. Patterns of combination of agnathia-otocephaly with other anomalies have led to postulation of the presence of different subgroups1, 3, 9, 11—isolated agnathia-otocephaly, agnathia-otocephaly with holoprosencephaly, agnathia-otocephaly with situs inversus and the combination of the latter two entities11. Prenatal diagnosis of otocephaly has been reported on several occasions4, 10, 12, 13 and in the past polyhydramnios was the first referral diagnosis. The abnormal profile is frequently a striking finding, with the typical hypoplastic lower midface often suggesting the differential diagnosis of Treacher–Collins or Goldenhar syndrome in combination with a Pierre–Robin sequence. The low-set or midline position of the ears is key to the diagnosis, but visualization of this feature is difficult using 2D ultrasound. Few previously reported cases were suspected to be abnormal prenatally, with the diagnosis only made after birth3, and in several papers it is reported that the diagnosis was only achieved in the third trimester2, 3. This apparent limitation of prenatal screening may reflect past practice and technology and the fact that in some countries accurate evaluation of the face is not part of a routine scan. However, we think that the wide uptake of first-trimester screening with demonstration of the fetal profile on the one hand, and the wide use of 3D ultrasound on the other, will contribute in the future to an early and more accurate diagnosis, as reported in recent case reports4, 12, 14. Third-trimester pregnancies with agnathia-otocephaly are often complicated by premature delivery due to polyhydramnios as a result of impaired swallowing3. Most cases die in utero or shortly after birth or are terminated after the anomaly is detected. One case has been reported in which a neonate with isolated agnathia-otocephaly was resuscitated following prenatal diagnosis and ex-utero intrapartum treatment (EXIT) procedure15, but the infant died on the third day of postnatal life. In the very few surviving infants with isolated agnathia the underdevelopment of the mandible and tongue prevented normal feeding and nasogastric tubes were installed to allow enteral nutrition. The use of 3D ultrasound facilitates, in complex facial malformations, appreciation of the nature and extent of the abnormality16. Agnathia-otocephaly is probably one of the diagnoses where 3D ultrasound helps in demonstrating the position and shape of the ears in addition to the facial features10, 13-15, 17. It can be helpful for parental counseling by plastic surgeons in less severe cases10 or, as shown in our case, can help parents decide on whether to continue with, or terminate, the pregnancy. SUPPORTING INFORMATION ON THE INTERNET The following supporting information may be found in the online version of this article: Videoclip S1 Three-dimensional rendering of the fetal face with the severe malformation: agnathia-otocephaly with cyclopia and holoprosencephaly. The authors thank Dr K. H. Dalicho for referring the patient and Dr Günther and Dr Pauli from the Institute of Pathology, MVZ Hochstr., GesundheitsZentrum Brandenburg GmbH for the pathologic examination and in particular for providing the postmortem photograph. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
https://doi.org/10.1002/uog.9009