Cystic hygroma (lymphangioma)

What it is

Cystic hygroma is a lymphatic malformation, a rare benign lymphangioma of the neck. It is a congenital lymphatic cyst in the posterior triangle caused by malformation and obstruction of the lymphatic system, that is by maldevelopment of lymphatic tissue, and it is a collection of dilated lymphatic sacs.

Among neck masses it is one of the posterior triangle masses, together with clavicular tumor and cold abscess.

Causes and risk

It is present by the age of 2 years. Cystic hygroma is also one of the clinical manifestations of Turner syndrome, where it is often diagnosed prenatally.

How it presents

The lump is a thin walled cyst in the posterior triangle that transilluminates. It is painless, soft and compressible, that is fluctuant, and it is cystic and multilocular. A posterior neck swelling in the lower 2/3 of the posterior neck triangle fits this picture.

Infection causes a sudden increase in size.