A cystic hygroma, also known as a cystic lymphangioma, is a rare, congenital, benign tumour of the lymphatic system. They may arise in any location of the lymphatic system, but are most common in the cervical-fascial region and particularly common in the posterior triangle of the neck. The tumours are typically filled with multiple cysts containing lymph.


  • Incidence: 0.50 cases per 100,000 person-years
  • Most commonly see in infants
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Cystic hygromas typically present at birth or within a few years following, with 90% being diagnosed before the age of 2 years. They are known associations with Turner syndrome and environmental factors such as alcohol abuse and viral illness during pregnancy.

Typical examination features:
  • occur anywhere within lymphatic system, but most common in the posterior triangle of the neck
  • cystic hygromas are more common on the left-side
  • soft and compressible
  • typically not painful
  • no movement on swallowing
  • transillumination is detected
  • may interfere with respiration or compromise the airway


Diagnosis and investigations:
  • consider and exclude other malignancy
  • ultrasound, CT or MR imaging

Differential diagnosis

Differential diagnosis of a neck lump in children:
  • congenital: branchial cyst, thyroglossal cyst, dermoid cyst, vascular malformation
  • inflammatory: reactive lymphadenopathy, lymphadenitis,
  • neoplastic: lymphoma


  • Observation (some tumours are small, static or slowly regress)
  • Surgical excision