cebocephaly
description
in cebocephaly, a small flattened nose with a single nostril is situated below hypoplastic, hypoteloric orbits. the philtrum of the upper lip is absent, leaving a smooth appearance. the head is usually malformed, being somewhat trigonocephalic. cebocephaly is part of a spectrum of ocular and facial malformations resulting from an abnormality in the development of the forebrain and frontonasal process, leading to holoprosencephaly. the eyes, orbits, and most of the midfacial structures may be absent; the eyes and orbits may be normally formed but closely set and with a single nostril; or the facial malformation may fit into the spectrum in between these extremes. the correlation between face and brain in holoprosencephaly suggests an intimate relationship between the developing prosencephalon and the neural crest cells which give rise to the frontonasal process. variation in severity may occur because of differences in magnitude, timing or susceptibility. several cases are reported with specific deletions in the long arm of chromosome 14, others with translocation trisomy 13.
diagnosis
the spectrum of anomalies accompanying holoprosencephaly are best appreciated ultrasonographically if several planes are visualised. the sagittal plane evaluates the fetal profile, including forehead, nose, upper and lower lip and jaw. this view is the most useful in identification of a proboscis or absence of nasal structures. a coronal view through facial structures involving both orbits, maxilla and the anterior portion of the mandible in one vertical plane will reveal single, fused or closely spaced orbits, abnormalities of sphenoid and ethmoid bones and the integrity of the nose and lips. a transverse or axial plane slightly caudal to the one commonly applied for determination of the biparietal diameter will evaluate the orbit(s) and upper lip. orbital biometry can be performed in this plane. recently, a new technique of three dimensional ultrasound visualization using surface and volume rendering has been developed. the application of this technology may enhance imaging of the fetal face and resolve some of the difficulties inherent in distinguishing between the malformations of the cyclopia- cebocephaly-ethmocephaly-median cleft face spectrum.
differential diagnosis
in ethmocephaly a proboscis is located between closely set eyes. in cyclopia a proboscis may be situated above a single eye, or fused eyes in a single orbit.
sonographic features
a small flattened nose with a single nostril, situated below hypoplastic, hypoteloric orbits
the head is often trigonocephalic
the philtrum of the upper lip is absent
associated syndromes
- acalvaria holoprosencephaly-facial dysmorphism
- agnathia holoprosencephaly-tetramelia
- aicardi
- alcohol
- aqueductal stenosis
- brachial amelia cleft lip/palate
- charge association
- chromosomal
- craniosynostosis holoprosencephaly
- diabetes insipidus coloboma-alobar holoprosencephaly
- ectopia cordis embryonal neoplasms
- familial, isolated
- goldenhar
- grote
- hartsfield
- holoprosencephaly-fetal hypokinesia
- holoprosencephaly-ntd-nerve palsy-deafness
- hydantoin
- lambotte
- lip synechia imperforate anus
- majewski variant chondrodysplasia
- martin
- maternal diabetes
- meckel-gruber
- meckel-like (fried)
- median cleft face other anomalies
- pallister-hall
- pseudotrisomy 13
- steinfeld
- thomas
- velo-cardio-facial
references
- hunter agw holoprosencephaly in human malformations and related anomalies. oxford university press, p27-38
- mcgahan jp, nyberg da, mack la sonography of facial features of alobar and semilobar holoprosencephaly ajr 154: 143-8
- nyberg da, mack la, bronstein a, hirsch j, pagon ra holoprosencephaly: prenatal sonographic diagnosis ajr 149: 1051-8
- cohen mm jr perspectives on holoprosencephaly: part 1. epidemiology, genetics and syndromology teratol 40: 211-235
- hegge fn, prescott gh, watson pt fetal facial abnormalities identified during obstetric sonography j ultrasound med 5: 679-684
- schinzel a, savoldelli g, briner j, schmid w prenatal ultrasonographic diagnosis of holoprosencephaly two cases of cebocephaly and two of cyclopia arch gynecol 236: 47-53
- toth z, csecsei k, szeifert gt, papp z prenatal diagnosis by ultrasound of midface defects associated with holoprosencephaly acta chirurgica hungarica 29: 215-221
- hsieh f-j, lee c-n, wu c-c, ko t-m, kao m-l, wong a-h, chen m-l, chen h-y antenatal ultrasonic findings of craniofacial malformations j formosan med assoc 90: 551-4
- turner gm, twining p the facial profile in the diagnosis of fetal abnormalities clin radiol 47: 389-395
pretorius dh, nelson tr fetal face visualization using three-dimensional ultrasonography j ultrasound med 14: 349-356 - bundy al, lidov h, soliman m, doubilet pm antenatal sonographic diagnosis of cebocephaly j ultrasound med 7: 395-8