Pathology

1. Cystic hygroma
   • Congenital cystic lymphatic malformation found in posterior triangle of the neck
   • Probably developmental abnormality formed during the coalecence of primitive lymph elements
   • Consists of thin-walled single or multiple interconnecting or separate cysts which insinuate themselves widely into the tissues at the root of the neck
2. Epidemiology
   • 50-65% present at birth but occasionally present late in childhood or adulthood

Approach

• As for neck examination

1. Inspect
   • Located in the posterior triangle
2. Palpate
   • Lobulated cystic swelling
   • Soft and fluctuant
   • Compressible (usually into another part of the cyst)
   • "Brilliantly transilluminable"

Completion

1. Examine oropharynx (large cyst may extend deeply beneath the sternocleidomastoid muscle into retropharyngeal space)
2. Ask patient how lump affects life

Complications of cystic hygromas

1. Before delivery
   • May obstruct delivery
2. After delivery
   • Respiratory obstruction
   • Obstruction of swallowing

Investigations to confirm diagnosis

1. CXR: map caudal extent of cystic hygroma
2. CT/MRI: especially if complex

Treatment options:

1. Non-surgical
   • Aspiration and injection of sclerosant (generally unsuccessful)
2. Surgical
   • Excision - may be partial to relieve symptoms or complete