What's your diagnosis based on these images in a first-trimester fetus?
(Images courtesy of Firoz Bhuvar, MD)
1. Distended jugular lymphatic sacs
The fetal jugular lymphatic sacs are distended bilaterally (see arrowheads). This is not a normal finding and is associated with increased nuchal translucency thickness and is also a marker for trisomy 21. Engorged jugular lymphatic sacs suggest abnormal lymphangiogenesis in this fetus.