Cystic Hygromas and Webbed Necks

A cystic hygroma ("moist tumor") is thought to form because of absent or delayed formation of lymphatico-venous connections, leading to lymphatic enlargement at the neck. The nuchal translucency is thought to represent a small cystic hygroma.

It is thought that delayed communication between the lymphatic and venous systems accounts for the resolution of cystic hygromas in some fetuses. In addition, some believe that the webbed neck and high hairline seen in patients with Turner syndrome are the sequella of resolved cystic hygromas.

References

Cystic Hygroma by Sabih D and Khan AN. eMedicine. Jul 17, 2008.