Cystic Hygroma

Assessment

Bilateral swellings: yes/no

Central nuchal ligament: yes/no

Maximum diameter:

Pleural effusion:

Pericardiac effusion:

Subcutanous oedema:

Ascites:

DV a-wave:

Tricuspid regurgitation: yes/no

Associated findings

Head/brain: ventriculomegaly, absent CSP/corpus callosum, microcephaly
Face: cleft, absent/hypoplastic nasal bone, prenasal oedema, anopthalmia, hypertelorism, micrognathia
Heart/thorax: cardiac abnormality, echogenic foci, pulmonary stenosis, CDH
Abdomen/renal: horseshoe kidney, hydronephrosis, duodenal atresia
Skeletal: limb contractures, short femur, clinodactyly, hypoplastic 5th finger, sandal gap
Size: fetal growth restriction

Differential diagnoses

Turner syndrome (Monosomy X): pleural effusion/ascites/hydrops, cardiac abnormalities, horseshoe kidney

Down syndrome (Trisomy 21): absent/hypoplastic nasal bone, prenasal oedema, nuchal fold thickness, intracardiac echogenic foci, duodenal atresia, echogenic bowel, hydronephrosis, short femur, sandal gap, clinodactyly/hypoplastic finger

Noonan syndrome: hypertelorism, pulmonary stenosis, fetal growth restriction

Fryns syndrome: anophthalmia, facial cleft, micrognathia, ventriculomegaly, CDH

Neu-Laxova syndrome: hypertelorism, microcephaly, agenesis of corpus callosum, limb contractures, fetal growth restriction

Multiple-pterygium sydrome: limb contractures, microcephaly, micrognathia

Useful phrases

We have discussed that around half of fetuses with a cystic hygroma will have a chromosomal abnormality, including Turner Syndrome (Monosomy X) and Down syndrome (Trisomy 21). Of the remaining fetuses, around half will have a single gene disorder (including Noonan Syndrome), and/or a cardiac abnormality, which may become apparent in later pregnancy or early life. In the absence of a chromosomal, genetic or cardiac abnormality, cystic hygromas may resolve and be unexplained, but there is an increased risk of fetal demise.