Diagnostic ultrasound ( PDFDrive )

CHAPTER 33 The Fetal Face and Neck 1143
A B C
D
E
F
FIG. 33.10 Holoprosencephaly. Nineteen-week fetus with trisomy 13 including multiple anomalies. (A) Bilateral cleft lip and palate. (B) Low-set
ears. (C) and (D) Proboscis and inferior vermian hypoplasia. (E) and (F) Semilobar holoprosencephaly.
Coloboma
Coloboma results from incomplete closure of the optic issure
and most oten afects the iris inferiorly 6 (Fig. 33.15). However,
it can afect any structure from the eyelid to the optic nerve or
retina. Vision may or may not be afected, depending on the
structures afected and the severity of the abnormality. Diagnosis
in utero depends on visualization of a focal bulge in the posterior
aspect of the globe. In cases where bones cause artifacts in this
region and this assessment is crucial, 3-D ultrasound 38 or MRI 39
can be helpful. Coloboma is a rare diagnosis (0.2 per 1000) 40
and may be associated with other anomalies and syndromes,
such as CHARGE syndrome (coloboma, heart defects, choanal
atresia, restriction of growth and development, genital and ear
anomalies).
Dacryocystocele
Dacryocystoceles result from obstruction of the nasolacrimal
ducts (Fig. 33.16). hese appear as cystic masses that may contain
low-level internal echoes, located inferomedially to the orbit in
the expected location of the nasolacrimal duct. here is usually
no mass efect on the globe, and there is no increased vascular
low in or around these masses. Diagnosis is usually made ater
30 weeks’ gestation; the nasolacrimal ducts do not complete
canalization until the third trimester. 41 he characteristic appearance
and location of dacryocystoceles should allow diferentiation
from other facial masses, such as teratomas (oten solid or mixed
cystic and solid, and may contain calciications) or hemangiomas
(solid, echogenic sonographic appearance, with increased vascular
low). he natural history of dacryocystoceles is variable, with
some resolving in utero, or postnatally with conservative measures
such as massage and application of warm compresses, and others
requiring probing or surgical intervention ater birth. 42
Congenital Cataracts
Congenital cataracts may be diagnosed on prenatal sonography,
which will show a rounded echogenic mass in the anterior portion
of the globe. Causes of congenital cataracts include genetic
disorders, infection, syndromes, and microphthalmia. 5 Some
cases are inherited by either autosomal dominant or autosomal
recessive transmission. his is a rare disorder, with a reported
incidence of approximately 3 per 10,000 births. 43
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