Overview

Lymphangioma is a benign malformation of the lymphatic system affecting the skin and mucous membrane.¹ The lymphatic system usually helps in the drainage of waste products and also helps in the defence mechanisms. Oxygenated blood usually travels through the arteries, and deoxygenated blood returns via the veins. The lymphatic system is a network which consists of lymphoid organs, lymph nodes and lymphatic channels. So these lymphatic channels behave like a tubular network which drains the fluid called lymph that is leaked from the blood vessels(arteries)  into the tissues, and these are drained back into the blood vessels( veins) via the lymph nodes. If this proper drainage does not occur, it is called oedema or swelling.² Lymphangiomas are usually classified as superficial or deep, or they can be classified as congenital or acquired. So the cystic hygroma(CH) is a congenital, deep type of lymphangioma. It is usually present at birth or diagnosed in the early stages of infancy. It usually affects the lymphatic system that drains the neck, clavicle and axillary region.³

Origin and epidemiology 

The origin of the lesion is not clear; it is said to be due to some developmental defect or cystic malformation of a dilated lymphatic channel.⁴ It is due to isolation or a defect in the proper connection of the lymphatic tissue from the lymphatic sac during the embryonic stage. This might cause a failure in the communication of the lymphatic or venous system. Dilation of these lymphatic tissues causes a cystic structure. Cystic hygroma is the most common lymphangioma, and accounts for 6% of lesions of early infancy and childhood. 50% of the cases are present at birth, and the rest 50% before the age of 2 years.⁵ When cystic hygroma appears before 30 weeks of gestation, it might be associated with syndromes such as Noonan syndrome, Turner's syndrome, trisomies, fetal hydrops and cardiac anomalies.⁴ In adults, it can occur rarely due to trauma or respiratory infection.  

Pathophysiology

The venous system usually carries blood back to the heart, and the lymphatic system drains the lymph into the venous system. The defect occurs in this step of drainage, and this leads to the accumulation of lymph in the form of cystic structures. It can enlarge in size, and it can be due to the accumulation of lymph, due to secondary infection or hemorrhage.³

Clinical presentation

Cystic hygroma can manifest anywhere in the body and appear as a diffuse lump or swelling that is often painless. The common locations are the neck region (75%), axilla, mediastinum, groin and also below the tongue. Based on the location of the swelling, there will be difficulty in moving the body parts, which can obstruct the respiratory system, cause pain, hoarseness of voice, dysphagia or even shortness of breath.  Sporadically, it may occur in the spleen, liver, kidney and intestine. It can be moved easily, and most importantly, it is translucent, i.e if we pass a light through the swelling, it glows, which means there is clear fluid in it. The swelling increases in size if a patient coughs or cries. It is non-neoplastic or non-cancerous.³,⁴

Diagnostic workup

The diagnosis is usually made by history and clinical examination. A history taken by a physician is very important. Usually, it appears early in life, mostly before the age of 2. Cystic hygroma in adults is rare. The individual should be screened for any chromosomal abnormalities, as sometimes they might be associated with syndromes. Swelling should be evaluated for any signs of infection, as the individual might come across symptoms such as fever, rigours and feeling unwell.

Other diagnostic methods used are USG(ultrasonography), CT( computed tomography) and MRI( magnetic resonance imaging). CT and MRI are used for treatment purposes to determine the exact size and location. It also helps in determining the proximity to important structures.³

Management 

If the lesions are small and do not impinge or involve other structures, then no need for surgery. If it causes disfigurement, respiratory distress, haemorrhage, infection or dyspnea, then treatment is advocated. Respiratory distress is the most common problem. Based on the size, anatomical location and complications, the treatment is modified. It can be surgery, sclerotherapy( now a matter of debate), drainage, laser, radiofrequency ablation and also cauterisation. Antibiotics, antipyretics and analgesics are prescribed based on the symptoms.⁶

Prognosis and follow-up

If cystic hygromas are not properly treated, then they might enlarge and cause complications based on the anatomical location. The prognosis also depends on the anatomical location. If a cystic hygroma was present prenatally, it has a bad prognosis. The surgery usually has a high success rate. Sclerosing agents can be used as an adjuvant. Some authors even suggest conservative treatment. Spontaneous regression has been noted in 1.6-16%^5,6. 

FAQs

When should a person with a cystic hygroma visit the doctor?

If the person experiences:  

• Sudden increase in size of the lesion
• Change in colour
• When there is a fluid leak
• Eating difficulty
• Redness or an increase in warmth
• Pain and discomfort
• Respiratory distress
• Change in the voice
• Bleeding or us formation

How can the development of cystic hygroma be prevented?

The exact cause is not clear, so it cannot be prevented. However, 

• Carry out the proper prenatal check-ups
• Chromosomal defects can be a cause 
• Avoid alcohol and smoking
• Eat a balanced diet
• Proper prenatal scanning can also detect the defect

Can a cystic hygroma disappear on its own?

In some cases, yes, there is spontaneous regression. In larger lesions, surgical intervention is often needed.

Summary 

Cystic hygroma is a congenital malformation mostly present at the time of birth. It is a defect in the lymphatic system, so that accumulation of lymph occurs. It usually presents as a swelling in the form of cystic spaces, like a soap bubble.  Based on the anatomical location and impingement of hygroma, it may cause respiratory distress, disfigurement, haemorrhage and dysphagia. Most of the cases occur in the neck region. Diagnosis is based on history and clinical examination. Haemorrhage and abscess formations are the main complications of CH. Management is based on the location, and the prognosis is good after surgery. Prenatal CH has a poor prognosis.