Cystic lymphatic disorder involving back and side of neck causing multiseptated fluid-filled mass

Cystic hygroma (CH) is typically large

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  Multiple internal septations is key to diagnosis

  
  
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  Different than isolated ↑ nuchal translucency because of size and septations

Associated with hydrops

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  Hydrops defined as fluid in 2 anatomic areas

  
  
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  CH counts as 1 area: Additional findings include pleural effusion, ascites, skin edema beyond neck

  
  
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  CH and hydrops can be diagnosed in 1st trimester

Highly associated with aneuploidy and syndromes (2/3)

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  Turner syndrome (monosomy X): Most common

  
  
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  Trisomy 21: 2nd most common

  
  
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  Others: Trisomy 18, trisomy 13, Noonan syndrome, other syndromes

Body/trunk lymphangioma

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  Less likely to cause hydrops, not associated with aneuploidy

Occipital encephalocele: Calvarial defect + brain anomaly

Cervical teratoma: Solid and cystic mass

CH + hydrops is grim finding, high mortality rates

Small isolated CH may resolve

Genetic counseling recommended for all cases

Use high-resolution probe to look for septations

Large CH may mimic pocket of amniotic fluid

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  Move patient to move fetus away from uterine wall

CH may be only “tapable” pocket of fluid for amniocentesis, karyotype is possible with this technique