A cystic hygroma is a mass that commonly occurs in the head and neck area. It is a birth defect.

A cystic hygroma occurs as the baby grows in the womb. It forms from pieces of material that carry fluid and white blood cells. Such material is called embryonic lymphatic tissue. After birth, a cystic hygroma usually looks like a soft bulge under the skin. The cyst may not be recognized at birth. It typically grows as the child does, and sometimes is not noticed until the child is older.

Sometimes, a cystic hygroma is seen when the baby is still in the womb using a pregnancy ultrasound. This can mean that the baby has a chromosomal problem or other birth defects.

A common symptom is a neck mass found at birth, or discovered later in an infant after an upper respiratory tract infection.

• Chest x-ray
• Ultrasound
• CT scan

If the cystic hygroma is detected during a pregnancy ultrasound, other ultrasound tests or amniocentesis may be recommended.

Treatment involves complete removal of the abnormal tissue whenever possible. However, cystic hygromas can often invade other neck structures, making this impossible.

Other treatments have been attempted with only limited success. These include:

• Chemotherapy medications
• Injection of sclerosing medications
• Radiation therapy
• Steroids

The outlook is good if surgery can totally remove the abnormal tissue. In cases where complete removal is not possible, the cystic hygroma commonly returns.

The outcome may also depend on what other chromosomal abnormalities or birth defects, if any, are present.

Complications may include:

• Bleeding
• Damage to structures in the neck caused by surgery
• Infection
• Return of the cystic hygroma

If you notice a lump in your neck or your child's neck, call your doctor.

Lymphangioma

Camitta BM. Abnormalities of lymphatic vessels. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 489.

Richards DS. Ultrasound for pregnancy dating, growth, and the diagnosis of fetal malformations. In: Gabbe SG, Niebyl JR, Simpson JL, eds. Obstetrics: Normal and Problem Pregnancies. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2007:chap 9.

Updated by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Seth Schwartz, MD, MPH, Otolaryngologist, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.