A lymphangioma is a rare, non-cancerous growth of the lymphatic system. This condition involves an abnormal collection of dilated lymphatic vessels that fail to drain lymph fluid properly, causing it to pool and form fluid-filled cysts. Lymphangiomas are congenital malformations, meaning they arise from errors during fetal development and are present at birth or become noticeable early in life.
Understanding the Types of Lymphangiomas
Lymphangiomas are classified based on the size of the abnormal lymphatic channels. The primary classification divides the malformations into macrocystic, microcystic, and mixed types.
Macrocystic lymphangiomas are characterized by large cysts, measuring greater than one or two centimeters in diameter. This type is frequently referred to as “cystic hygroma.” These larger lesions present as soft, deep masses most commonly located in the head, neck, and axilla.
In contrast, microcystic lymphangiomas consist of small, pimple-sized cysts, measuring less than one or two centimeters. Microcystic lesions often present closer to the skin surface, where they are sometimes called “lymphangioma circumscriptum.” Their appearance is often described as a cluster of small, translucent vesicles. A mixed lymphangioma combines the characteristics of both types, featuring both large cystic spaces and small channels within the same lesion.
How Lymphangiomas Develop
The formation of a lymphangioma results from a failure of the lymphatic system’s development during early embryonic growth. The lymphatic system begins as primitive sacs arising from developing veins. The malformation occurs when these sacs fail to properly reconnect with the central venous system. This disconnection prevents lymph fluid from draining back into the bloodstream, leading to the dilation of the affected lymphatic channels.
While this is a developmental anomaly, it is not typically inherited. A significant proportion of these malformations are associated with somatic activating mutations in the PIK3CA gene. This specific gene mutation affects a pathway that regulates cell growth, contributing to the abnormal vessel development. Lymphangioma formation is not caused by any particular action or lifestyle factor during pregnancy.
Identifying Symptoms and Confirming Diagnosis
A lymphangioma is usually noticed early in life as a soft, compressible, and non-tender mass. The most common sites for these lesions are the head, neck, axilla, and groin. Superficial microcystic lesions may appear as clusters of tiny, blister-like bumps on the skin, sometimes leaking clear lymphatic fluid.
The main concern is the potential for complications related to size and mass effect. Large lesions, especially those in the neck, can press on the trachea or esophagus, causing breathing or swallowing difficulties. The lesion can also become painful or inflamed if a secondary infection, such as cellulitis, develops.
The diagnostic process begins with a physical examination, noting the characteristic soft, doughy consistency of the mass. Many larger macrocystic lesions are first detected prenatally during a routine ultrasound examination. Imaging techniques are then employed to confirm the diagnosis and map the extent of the malformation.
Ultrasound is the initial imaging modality of choice to confirm the cystic nature of the mass and rule out other possibilities. Magnetic Resonance Imaging is the preferred method to delineate the lesion’s full anatomical extent and its relationship to surrounding nerves and organs. The detailed images provided by MRI help clinicians distinguish the lymphangioma from other vascular masses and plan the management strategy.
Current Approaches to Management
The management of a lymphangioma depends on its type, size, and whether it is causing symptoms. For small lesions that are not causing pain or functional compromise, a strategy of watchful waiting is used.
For symptomatic or larger lesions, a minimally invasive technique called sclerotherapy has become a prominent treatment option. Sclerotherapy involves injecting a sclerosant directly into the cysts to cause a controlled inflammatory reaction. This reaction leads to the collapse and scarring of the abnormal lymphatic channels, resulting in the gradual shrinkage of the malformation.
Commonly used sclerosant agents include OK-432 and the antibiotic Doxycycline. Sclerotherapy is effective for macrocystic lesions, achieving high success rates and avoiding risks associated with open surgery. Surgical excision, the historical standard, is now reserved for lesions that are well-defined, easily accessible, or resistant to injection therapy. Complete surgical removal can be challenging because lymphangiomas often infiltrate surrounding healthy tissues, increasing the risk of recurrence.