URR- ANOMALIES OF THE FETAL SKULL & FACE
acrania
1. AKA exencephaly 2. lack of cranial bone formation 3. cerebral tissues form but in abnormal way 4. identified as early as 12 weeks 5. increased AFP (neural tube defect)
fetal goiter
1. anterior neck mass 2. result = tracheal compression postnatal respiratory issues 3. cause = by maternal conditions or fetal hypothyroidism 4. PUBS can be performed to assess fetal thyroid status
cystic hygroma (CH)
1. collection of lymphatic fluid from obstruction 2. occurs on posterior neck (80%) 3. strongly associated with chromosomal abnormalities affecting AFP levels, polyhydraminos, hydrops, pleural effusion, ascited & anasarca 4. appears similar to encephalocele, cystic teratoma, meningomyocele 5. differentiated from encephalocele by evaluating cranial structure for presence of opening
encephalocele sonographic appearance
1. complex cystic mass connected to cranium 2. abnormal appearance of intracranial structures
teratoma
1. composed of ectodermal tissues 2. forms in many locations- usually along midline of body 3. pharynx, neck, sacrum, brain & skull sutures
hypotelorism
1. decreased distance b/w eyes 2. best evaluated for measurement in axial view of head 3. interocular distace below 5th percentile 4. commonly seen with holoprosenencephaly/median cleft face 5. associated with fetal alcohol syndrome/microcephaly
coronal plane facial evaluation
1. demonstrates nose & upper lips 2. evaluate lens of both eyes
dolichocephaly
1. elongated OFD 2. long, narrow head 3. associated with craniosynostosis, breech presentation & oligohydraminos
axial plane facial evaluation
1. evaluate orbits & eyes, superior lip & palate 2. mandible should demonstrate contiguous "U" shape 3. maxilla should demonstrate contiguous "V" shape
sagittal plane facial evaluation
1. fetal profile assessment 2. possible deformation of forehead or nose 3. measure philtrum (vertical groove in upper lip) 4. evaluate nasal bone, facial angle, chin/jaw positioning 5. confirm mandible & maxilla aligned at their midpoints
cyclopia
1. formation of single ocular cavity 2. located along midline of face 3. associated with other midline facial & cranial defects
meningocele
1. herniation of meninges ONLY through opening in skull 2. cystic structure seen in posterior aspect of skull 3. increased MSAFP
fetal goiter sonographic appearance
1. homogeneous 2. central neck mass 3. well-defined borders
cebocephaly
1. hypotelorism & a nose with single nostril 2. associated with holoprosencephaly
ethmocephaly
1. hypotelorism with no nose 2. only a proboscis present 3. associated with holoprosencephaly
macrocephaly
1. increase fetal head size 2. HC = over 98th percentile for age 3. BPD & HC = 2 or more standard deviations above average for gestational age 4. associated with hydrocephalus, hydranencephaly, beckwith wiedemann syndrome
hypertelorism
1. increased distance b/w eyes 2. best evaluated for measurement in axial view of head 3. interocular distance = above 95th percentile 4. associated with cephalocele, craniosynostosis, trisomy 21, frontonasal dysplasia, meningoencephalocele, noonan syndrome, trisomy 13, turner syndrome
cystic hygroma identified in 1st trimester
1. indicates trisomy 21 2. low MSAFP
cystic hygroma identified in 2nd trimester
1. indicates turner syndrome 2. low MSAFP
encephalocele
1. meninges & brain tissue herniation through bony defect in calvarium (skullcap) 2. most in posterior/occipital location 3. leads to CSF obstruction of flow 4. poor prognosis 5. can be part of meckel gruber syndrome 6. can be part of pentalogy of cantrell
absent nasal bone
1. midsagittal plane 2. identify tip of nose & angle the beam until perpendicular to nasal bone to improve reflection 3. normal nasal bone appears like equal sign from skin layer being echogenic similar to bone 4. associated with trisomy 21
anencephaly
1. most common NTD 2. absence of upper cranial vault & cerebral tissue 3. eyes = present but exophthalmos present (frog eyes) 4. seen as early as 12 weeks 5. seen with other spinal defects & polyhydraminos 6. increased AFP
cleft lip/palate
1. most common facial defect- more common in males 2. most common type = unilateral cleft lip with cleft palate 3. medial cleft seen with congenital anomalies 4. midline or median cleft lip associated with other midline cranial defects like holoprosencephaly 5. assymmetric facial clefts associated with amniotic band syndrome 6. best evaluated @ 20 weeks evaluated in coronal views & extent of condition evaluated in axial planes 7. seen on u/s as anechoic space extending from nostrils through the lip 8. associated with polyhydraminos, flattened nostrils, hypertelorism 9. isolated cleft palate commonly associated with Pierre robin sequence
cystic hygroma occurring as an isolated abnormality
1. no change in MSAFP levels 2. can be surgically removed with good prognosis
lemon shaped skull
1. normal 2. open neural tube defects 3. chiari II malformation
epignathus
1. pharynx teratoma 2. grows out of mouth 3. may cause neck to become hyperextended
ear creases
1. pits or creases in lob & skin near ear 2. associated with beckwith-wiedemann syndrome
low-set ears
1. positioned 2 or more standard deviations from normal 2. associated with trisomy 13, 18 & 21
craniosynostosis
1. premature ossification of 1 or more skull sutures 2. causes abnormally shaped calvarium & abnormal facial features 3. restricts cerebral growth/development 4. associated with thanatophoric dysplasia, apert, crouzon & pfeiffer syndromes 5. demonstrated as abnormal irregular skull shape in transverse axial view 6. presents as clover leaf skull/strawberry skull
frontal bossing
1. prominent forehead with absent/hypoplastic nasal bone 2. commonly seen with trisomy 21
brachycephaly
1. shortened OFD 2. very round head 3. associated with trisomy 21, 18 & craniosynostosis
microtia
1. small ear 2. strong association with trisomy 21
microcephaly
1. small fetal head for GA 2. HC below normal by > 2 standard deviations 3. associated with porencephaly, lissencephaly, holoprosencephaly, maternal phenylketonuria, fetal alcohol syndrome & intrauterine infections 4. seen with hypotelorism, trisomy 13, 18 & meckel gruber syndrome
wormian bones
1. small ossification centers within cranial sutures 2. associated with trisomy 21, cleidocranial dysplasia, osteogenesis imperfecta
proboscis
1. soft tissue mass protruding from anterior/superior face 2. seen with arhinia & orbital abnormalities 3. associated with holoprosencephaly
cystic hygroma sonographic appearance
1. thin walled complex mass with septations 2. normally extends posteriorly from neck
micrognathia
1. undersized jaw 2. best seen in sagittal plane 3. associated with absent mandibular gap 4. can correct itself with growth & teeth formation 5. seen with polyhydraminos from dysphagia (70%), trisomy 18 & pierre robin syndrome 6. associated with increased risk of acute neonatal respiratory distress 7. tongue can obstruct airway during delivery
macroglossia
1. unusually enlarged tongue extending beyond teeth or alveolar ridge 2. related to amyloidosis, hypothyroidism, overgrowth/chromosomal disorders 3. leads to fetal dysphagia & polyhydraminos 4. seen with beckwith-wiedemann syndrome, trisomy 21, triploidy
fetal cataracts
1. vitreous(fluid) & lens of eye normally hypoechoic & lens outline/orbit wall are hyperechoic 2. best evaluated in coronal view demonstrating lens of eye 3. cataract formation causes echogenic lens with central clouding or complete opacity
anotia
absence of external ear
cloverleaf shaped skull
associated with thanatophoric dysplasia
strawberry shaped skull
associated with trisomy 18
agnathia
complete or partial absence of jaw
normal ossification of cranium
ossified by 15 weeks & easily visualized
retrognathia
posteriorly displaced jaw