Cystic hygroma

What it is

Cystic hygroma is a lymphatic malformation, a rare benign lymphangioma of the neck. It is a congenital lymphatic cyst of the posterior triangle caused by malformation and obstruction of the lymphatic system, and it is described as due to maldevelopment of lymphatic tissue. What is felt is a collection of dilated lymphatic sacs. Among neck masses it belongs to the posterior triangle group, alongside clavicular tumor and cold abscess, and in the differential of neck masses lymphangioma is listed with the benign neoplastic masses.

Causes and risk

It is present by the age of 2 years, and it can be seen in a newborn. It is one of the clinical manifestations of Turner syndrome, where it is often diagnosed prenatally, alongside short stature, webbed neck, shield chest with widely spaced nipples and lymphoedema of the neonate.

How it presents

The swelling is posterior, in the lower 2/3 of the posterior neck triangle, and it lies in the subcutaneous tissue just beneath the skin. It is a thin walled cyst that transilluminates: painless, soft and compressible, fluctuant, and brilliantly transilluminant. Infection causes a sudden increase in size.