Cystic Hygroma

• Cystic hygroma (CH) is a cluster of cysts in the lymph drainage system that usually affects the head and neck of children (fetuses and newborns to age 2 years).
• Cystic hygromas are congenital malformations in the lymph system.
• The cause is unknown but may be related to genetic changes in the fetus.
• Symptoms and signs include the appearance of clusters of cysts that are sometimes visible with the naked eye and may cause breathing difficulties, feeding problems, sleep apnea, and failure to thrive.
• If the cystic hygroma is not visible, it still can be diagnosed using CT scan, MRI scan, ultrasound and other techniques.
• Although medical treatment can be used, consisting of drugs that shrink down the cysts, many clinicians prefer surgical treatment to remove all of the cystic tissue.
• Although many patients have a good outcome, there are several indicators like abnormal fluid accumulation in two more fetal compartments like heart or lungs (fetal hydrops) or thickness of the lesion wall that suggest a poor outcome.
• Cystic hygromas are very infrequently seen in adults.

The cystic hygroma is a lymphatic lesion composed of a cluster of cysts that can appear in almost any area of the body, although it usually affects the head and neck (about 75%), most often on the left side. Cystic hygromas (CH) are also termed cystic lymphangiomas or macrocystic lymphatic malformations. 

The cause of cystic hygromas is not known. 

Although some patients have visible lesions to make the diagnosis on examination, others do not. The soft tissue lesions can be visualized with MRI scan, CT scan, ultrasound, and occasionally even with X-rays. Other studies such as airway fluoroscopy and lymphoscintigraphy (lymph node mapping by radiographic imaging) have been used. Also, endoscopic biopsy has been used for diagnosis.

Ultrasound has been used to diagnose cystic hygromas in fetuses as early as the first trimester.

The symptoms and signs of cystic hygroma vary with the location of the cluster of cysts. However, because many are present in the neck, they can produce symptoms that range from none to severe. Signs and symptoms of cystic hygroma are as follows:

• clusters of clear, black, or red vesicles on buccal mucosa or the tongue (microcystic form)
• large cysts with overlying bluish or normal-appearing skin (macrocystic form)
• sleep apnea, occasionally obstructive
• breathing difficulties
• feeding difficulties
• failure to thrive (especially in children who have involvement of the gastrointestinal tract)
• intra-lesional bleeding (rare)

Some clinicians prefer to “watch and wait” in children who have a cystic hygroma and no symptoms. However, if symptoms develop, there are two main treatments -- medical, using chemicals to scar or obliterate the cysts and surgical excision of the cystic tissue. Some authors consider surgical removal as the preferred treatment. Other techniques, such as radiofrequency ablation and laser induced thermotherapy, have also been used to treat the lesions. Parents should discuss treatment options that would be best for their child with their child's treatment team, usually composed of the child's pediatrician and a surgical specialist and/or otolaryngologist.

The prognosis of cystic hygromas is variable and can range from good to poor. For example, if most but not all cystic hygroma tissue is removed, there is a 15% chance of recurrence.

Prognosis decreases when the cystic hygroma is in fetuses and in those with excessive neck thickening. Also, if the fetus also has genetic abnormalities the prognosis is poorer.