14 WEEKS GESTATION FOR NT SCAN
|
Diffuse subcutaneous edema of fetal thorax and abdomen with mild bilateral pleural effusion |
|
Large cystic fluid collection in the nape of neck extending to both sides with few internal septations and diffuse subcutaneous edema of fetal cranium |
·
Nuchal cystic hygromas are characterized by single or multiple
congenital cysts of the lymphatic system most commonly found within the soft
tissues of the neck.
·
The frequency is one in 875 spontaneous abortions.
·
Nuchal cystic hygromas are the clinical consequence of a delay in development or absence of the communications that
normally develop between the jugular lymph sacs and the internal jugular veins
at approximately 40 days gestation.
·
The obstructed jugular lymph sacs dilate along the paths of least
resistance into the posterior and lateral cervical areas.
·
Late communication of the sacs with the internal jugular vein may
be manifest by redundancy of the posterior nuchal skin, neck webbing, and
elevation and anterior rotation of the ears.
·
Complete lymphatic obstruction may be associated with nonimmune
fetal hydrops, which is frequently fatal.
·
About 78% of patients with cystic hygroma are chromosomally
abnormal; 58% have a karyotype associated with Turner syndrome phenotype; while
autosomal trisomies and various structural abnormalities made up the remaining
20%.
·
The most common associated structural malformations are cardiac
abnormalities.
·
Even among the 22% of fetuses with normal chromosomes, various
physical anomalies are present.
·
Other syndromes associated with cystic hygromas are Noonan
syndrome (autosomal dominant), Pena-Shokeir syndrome, Down syndrome, Robert’s
syndrome (autosomal recessive) and multiple pterigium syndrome (autosomalrecessive,
X-linked).
Ultrasonographic findings
·
The fetus presents with large bilateral cystic areas, termed
cystic hygromas develop within the skin in the posterolateral aspect of the
neck.
·
They may grow so large that they lie adjacent to each other.
·
It then appears that there is a cystic mass arising from the back
of the neck with one to three septa in the center.
·
The skin thickening is most pronounced in the upper torso and
cranium.
·
Hydrops occurs in more severe cases with large pleural effusions,
pericardial effusions and ascites.
·
Amniotic fluid is often reduced.
·
Placenta is normal or thickened with hydrops.
·
Differential diagnosis is encephalocele or meningocele (the mass
is posterior and is a single mass. It is associated with a cranial defect) and
unfused amniotic membrane.
Reference : Antenatal
Diagnosis and Management of Nuchal Cystic Hygroma: A Case Report in the Yaounde
Central Maternity, Cameroon; Clinics in Mother and Child Health; Vol. 8 (2011).