eMedicine Specialties > Pediatrics: Surgery > Otolaryngology

Cystic Hygroma

Author: Jason L Acevedo, MD, Resident Physician, Department of Otolaryngology-Head and Neck Surgery, Walter Reed Army Medical Center
Coauthor(s): Rahul K Shah, MD, FAAP, Assistant Professor of Otolaryngology and Pediatrics, George Washington University, Children's National Medical Center; Attending Physician, Department of Otolaryngologoy, Children's National Medical Center; Holly L Neville, MD, Assistant Professor of Clinical Surgery, Division of Pediatric Surgery, University of Miami Miller School of Medicine; Michael D Poole, MD, PhD, Consulting Staff, Georgia Ear Institute
Contributor Information and Disclosures

Updated: Jul 18, 2008

Introduction

Background

First described by Wernher in 1843, cystic hygroma (CH) is a cystic lymphatic lesion that can affect any anatomic subsite in the human body. CH usually affects the head and neck (approximately 75%), with a left-sided predilection. Within the neck, the posterior triangle tends to be most frequently affected. Approximately 20% of CHs occur in the axilla; more infrequent subsites include the mediastinum, groin, and retroperitoneum. CH is synonymous with cystic lymphangioma, which is also known as a macrocystic lymphatic malformation and was first described in 1828 by Redenbacker.

Pathophysiology

Lymphangiomas are thought to arise from a combination of the following: a failure of lymphatics to connect to the venous system, abnormal budding of lymphatic tissue, and sequestered lymphatic rests that retain their embryonic growth potential. These lymphatic rests can penetrate adjacent structures or dissect along fascial planes and eventually become canalized. These spaces retain their secretions and develop cystic components because of the lack of a venous outflow tract. The nature of the surrounding tissue determines whether the lymphangioma is capillary, cavernous, or cystic.

CHs tend to form in loose areolar tissue, whereas capillary and cavernous forms of lymphangiomas tend to form in muscle. Studies using cell proliferation markers have demonstrated that lymphangioma enlargement is related more to engorgement than to actual cell proliferation. Molecular studies suggest that vascular endothelial growth factor C (VEGF-C) and its receptors may play an important role in the development of lymphatic malformations.

In addition to congential development, lymphangiomas can be acquired. They can arise from trauma (including surgery), inflammation, or obstruction of a lymphatic drainage pathway.

Frequency

International

The incidence of CH is estimated to be 1 case per 6,000-16,000 live births.

Mortality/Morbidity

Mortality has been reported to be as high as 2-6% in some series, usually secondary to pneumonia, bronchiectasis, and airway compromise. Obviously, this figure is pertinent in the larger-sized lesions.

As expected, morbidity depends on the anatomic location of the CH. In general, morbidity is related to cosmetic disfigurement and impingement on other critical structures such as nerves, vessels, lymphatics, and the airway.

Race

Most series report no racial predominance, although a decreased incidence in African Americans has been described.

Sex

The sex distribution is equal.

Age

Most cystic hygromas (50-65%) are evident at birth, with 80-90% of CHs presenting by age 2 years. Some authors believe that all CHs are present at birth, although they may have not yet fully manifested at that time.

CH can be visualized using abdominal ultrasonography by 10 weeks' gestation, although transvaginal ultrasonography provides superior detail. Fast-spin MRI can also be used to determine the extent of fetal CH. Elevated alpha fetoprotein levels in amniocentesis fluid has been reported in pregnancies with CH.

Clinical

History

The presenting signs and symptoms of the cystic hygroma (CH) vary depending on the lesion's location.

• The microcystic form of lymphangioma tends to predominate over CH in the oral cavity and oropharynx. Microcystic lymphangiomas commonly appear as clusters of clear, black, or red vesicles on the buccal mucosa or tongue.
• CHs tend to predominate below the mylohyoid muscle and can involve both the anterior and posterior triangles of the neck.
• The cysts are typically large and thick walled and have little involvement of surrounding tissue. The overlying skin can take on a bluish hue or may appear normal.
• CHs often present after a sudden increase in size secondary to infection or intralesional bleeding. Spontaneous decompression or shrinkage is uncommon.
• Rarely, children with CH display symptoms of newly onset obstructive sleep apnea syndrome (OSAS). This situation may involve children with CH or other space-occupying lesions of the supraglottis or paraglottic region. Suprahyoid lymphangiomas tend to cause more breathing difficulties than infrahyoid lesions.
• Potentially life-threatening airway compromise that manifests as noisy breathing (stridor) and cyanosis is a possible symptom of lymphangiomas.
• Feeding difficulties, as well as failure to thrive, may alert the clinician to a potential lymphangioma. This is especially true when the lesion affects structures of the upper aerodigestive tract.

Physical

• CHs are typically soft, painless, compressible (doughy) masses.
• A CH typically transilluminates.
• In children who present with CH of the neck, closely evaluate for tracheal deviation or other evidence of impending airway obstruction.
• Closely inspect the tongue, oral cavity, hypopharynx, and larynx because any involvement may lead to airway obstruction.
• Referral to an airway expert (otolaryngologist) to potentially perform a fiberoptic airway evaluation is justified in patients with a lymphatic malformation.

Causes

Karyotypic abnormalities are present in 25-70% of children with CH. CH has been noted to be more common in persons with Turner syndrome, Down syndrome, and trisomy 18 and 13, although these are not considered a cause.

In addition, several nonchromosomal disorders, including Noonan syndrome, Klinefelter syndrome, Fryns syndrome, multiple pterygium syndrome, and achondroplasia are associated with an increased incidence of CH. Intrauterine alcohol exposure has been associated with the development of lymphangiomas. Dissolution of bone caused by either lymphangiomas or hemangiomas is termed Gorham-Stout syndrome.

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