Cystic Hygroma: Symptoms, Types, Causes and Treatment

Cystic hygroma is a rare, benign malformation of the lymphatic system that most commonly presents in infants and young children, but can occasionally be diagnosed in adults. Characterized by fluid-filled cystic spaces, this condition can vary widely in its appearance, severity, and prognosis. Understanding the symptoms, types, underlying causes, and evolving treatment options for cystic hygroma is crucial for patients, families, and healthcare professionals. In this article, we dive deep into each aspect, using current research to paint a clear, human-centered picture of this complex condition.

Symptoms of Cystic Hygroma

Cystic hygroma often presents as a soft, painless, and compressible mass, most commonly located in the neck. However, the spectrum of symptoms can be broad, influenced by the size, location, and extent of the lesion. Early detection is important, as some cases may cause serious complications, especially if vital structures are involved.

Symptom	Description	Typical Locations	Source(s)
Swelling	Fluctuant, soft, compressible mass	Neck (posterior triangle), axilla, thorax	1,3,9
Respiratory distress	Difficulty breathing, cough, fever	Thoracic involvement	1
Skin changes	Usually normal appearance over swelling	Overlying affected area	3
Pain	Usually absent; swelling is painless	Common sites	3
Transillumination	Cystic mass lights up with light	Neck, axilla	3

Table 1: Key Symptoms

Common Presentations

Most often, cystic hygroma manifests as a soft, fluctuant swelling in the neck—specifically the posterior triangle—though it may also occur in the axilla, thorax, retroperitoneal, or inguinal regions. These swellings are typically compressible, painless, and freely mobile, distinguishing them from other neck masses. The skin over the lesion usually appears normal, and lymphadenopathy is generally absent 3.

Complications and Severe Symptoms

When cystic hygromas are large or located in the thorax, they can present with more severe symptoms. For example, massive thoracic cystic hygromas may cause respiratory distress, cough, or even fever due to compression of the airways or secondary infection. Hemorrhage into the cysts can also occur, leading to acute or rapidly progressing symptoms 1.

Diagnostic Clues

A notable feature is transillumination: the cystic spaces light up when a light is applied, aiding diagnosis. However, not all cystic masses will transilluminate, especially if they contain blood or are infected 3.

Types of Cystic Hygroma

Cystic hygromas are part of a broader group of lymphatic malformations and can be classified based on location, structure, and age of presentation. This diversity affects both clinical management and prognosis.

Type	Description	Commonality/Location	Source(s)
Cervical	Occurs in the neck, often posterior	75–90% of cases	3,9
Axillary	Found in the armpit	~20% of cases	3
Thoracic	Confined to chest cavity/mediastinum	Rare; complex to manage	1,3
Multiloculated	Multiple cystic spaces	Often in larger lesions	2,3
Fetal (Nuchal)	Detected prenatally, around the neck	Associated with poor prognosis	2

Table 2: Main Types

Location-Based Types

• Cervical Cystic Hygroma: This is the most frequent type, accounting for the vast majority of cases. The posterior triangle of the neck is the classic site, but lesions may cross the midline and extend into the axilla or mediastinum 3,9.
• Axillary and Thoracic Types: Less common, these can be more challenging to treat. Thoracic lesions, for instance, may envelop vital structures, making surgical intervention risky and recovery complex 1,3.

Structural Variants

Cystic hygromas can be simple (single cyst) or multiloculated (multiple cystic spaces). Multiloculated lesions are often larger and more infiltrative, making complete removal difficult 2,3.

Fetal and Congenital Forms

Fetal cystic hygromas (often called nuchal hygromas) are detected by prenatal ultrasound. These are typically located around the neck and can be associated with severe complications such as hydrops fetalis or fetal demise. The prognosis in fetal cases is generally poor, especially when associated with chromosomal abnormalities 2.

Causes of Cystic Hygroma

The underlying causes of cystic hygroma are multifactorial, involving developmental, genetic, and sometimes familial components. Understanding these helps guide both prognosis and potential genetic counseling.

Cause	Mechanism/Association	Prognostic Significance	Source(s)
Developmental defect	Failure of lymphatic-venous connection	Common underlying mechanism	2,3
Genetic mutations	Variants in lymphangiogenesis genes	Familial clustering, variable	4
Chromosomal abnormalities	Strong association with Turner’s syndrome, others	Poor fetal prognosis	2,4
Hereditary factors	Autosomal dominant/recessive inheritance	Prognosis depends on inheritance	4

Table 3: Key Causes

Developmental Origins

Cystic hygroma is fundamentally a congenital malformation: it arises from a failure of the embryonic lymphatic system to properly connect with the venous system, especially in the neck region. This defect leads to the formation of abnormal, dilated lymphatic channels that accumulate fluid 2,3.

Genetic and Chromosomal Associations

There is a strong association between fetal cystic hygroma and chromosomal abnormalities, particularly Turner’s syndrome (45,XO). In one study, 73% of fetuses with cystic hygroma had Turner’s syndrome, while others had various genetic mutations or syndromic features 2. Recent genetic studies have identified mutations in genes involved in vascular and lymphatic development, such as KDR and KRIT1, suggesting a possible hereditary basis, especially in cases with a normal karyotype 4.

Hereditary Patterns

Cystic hygroma can sometimes be inherited in an autosomal dominant or recessive manner. Familial clustering and similarities with hereditary lymphedema have been reported, though the exact genetic mechanisms are still being investigated. Autosomal dominant inheritance may be associated with a better prognosis compared to recessive forms 4.

Treatment of Cystic Hygroma

Treatment for cystic hygroma has evolved considerably, moving from traditional surgical approaches to minimally invasive therapies. The choice of treatment depends on the size, location, and complexity of the lesion, as well as the patient's age and overall health.

Treatment	Description/Method	Pros/Cons	Source(s)
Surgery	Excision of lesion	Mainstay, but risk of recurrence/injury	1,3,6,7,9
Bleomycin injection	Sclerosing agent injected into cyst	High success, fewer complications	5,6
OK-432 injection	Sclerosing therapy (bacterial derivative)	High regression rates, minimal scarring	8
Other Sclerotherapy	Various agents for chemical ablation	Varying efficacy	5,6,8

Table 4: Main Treatments

Surgical Excision

Surgery has been the traditional mainstay of treatment. The goal is to remove the entire lesion, but this is often challenging due to the infiltrative nature of cystic hygromas, which can entwine nerves, blood vessels, and muscles. Complete excision may not always be possible, especially in complex thoracic or multiloculated cases. Surgery carries risks of recurrence, nerve injury, and postoperative complications such as chylothorax (as seen in thoracic cases) 1,3,6,7,9.

Sclerotherapy

Bleomycin

Bleomycin, an antitumor antibiotic, is now widely used as a sclerosing (scarring) agent injected directly into the cystic spaces. Clinical studies show excellent or good responses in the majority of patients, with minimal side effects and avoidance of surgical scars or nerve damage. Bleomycin can be administered in solutions or specialized emulsions, with emulsion forms potentially offering greater efficacy 5,6.

OK-432

OK-432 (Picibanil), derived from an inactivated strain of Streptococcus pyogenes, is another effective sclerosing agent. It is injected into the cysts and induces a local inflammatory reaction, leading to shrinkage or complete resolution of the lesion. Studies report high rates of complete regression, minimal discomfort (short-term fever or inflammation), and no scarring 8.

Other Modalities

There are other sclerosing agents under investigation, and the choice may depend on the size, location, and accessibility of the lesion, as well as the expertise available. Management is often tailored to the individual.

Multidisciplinary Approach

Given the complexity and potential for recurrence, especially in large or thoracic lesions, a multidisciplinary team—including pediatricians, surgeons, radiologists, and genetic counselors—is often required to optimize care 1,7,9.

Conclusion

Cystic hygroma remains a challenging but increasingly manageable condition thanks to advances in understanding its presentation, origins, and treatment options. Key points include:

• Symptoms: Usually a painless, compressible swelling, most often in the neck; severe cases can cause respiratory distress or other complications.
• Types: Classified by location (cervical, axillary, thoracic) and structure (simple, multiloculated); fetal forms are often more severe.
• Causes: Result from developmental defects, often with genetic or chromosomal associations, particularly Turner’s syndrome; some cases show hereditary patterns.
• Treatment: Surgery remains standard but is often supplemented or replaced by minimally invasive sclerotherapy (bleomycin, OK-432) with high success and fewer complications.

In summary:

• Early recognition and accurate diagnosis are vital.
• Treatment should be individualized, balancing efficacy and risk.
• Genetic counseling may be indicated, especially in familial or fetal cases.
• Multidisciplinary care offers the best outcomes, especially for complex or recurrent lesions.

With ongoing research and improved therapeutic options, the outlook for patients with cystic hygroma continues to improve.