Lymphatic malformations (synonyms and inclusions: cavernous lymphangioma; lymphangioma circumscriptum; macrocystic and microcystic lymphatic malformations)

Lymphatic malformations (LMs) are rare, sporadic, focal lesions composed of dilated lymphatic channels disconnected from the lymphatic system. Lesions can be macrocystic, microcystic, or combined.

This chapter is set out as follows: 

• LMs are formed in embryo, but not all LMs are visible at birth 
• While many are apparent by two years of age, others do not present until puberty, pregnancy or after trauma

Distribution

• Lesions can occur at any site, although are most common on the neck, chest wall, and axilla
• While usually localised, LMs can occasionally be widespread (diffuse) - when lymphatic malformations are widespread in bone and soft tissue, the condition may be referred to as lymphangiomatosis

Morphology

• LM can be made up of macrocysts (large pockets containing lymph), or microcysts (very small pockets of lymph) - many LMs have both
• Multilobulated, well‐defined lesions that are translucent, soft, but only slightly compressible on palpation, often with a frogspawn-like appearance
• Lesions can be clear, but become blue-purple when intracystic bleeding occurs
• Dermoscopically typical clods have the hypopyon sign with a two-tone appearance having a darker red or bluish colour at the base and a lighter yellow or pink colour at the top. The clods are separated by pale septae. Sometimes individual vessels can be seen feeding the clods
• Predominantly microcystic lesions are mostly located on the head and neck arising as ill‐defined vesicular plaques, which often invade adjacent structures
• Deeper involvement of the lymph system can occur that can be associated with lymphoedema

Associations

• Intralesional bleeding or infection can give rise to sudden pain - recurrent erysipelas/cellulitis are major complications that need to be treated rapidly as they can evolve into septicaemia
• Overgrowth (hypertrophy) and swelling of any affected area including the lips, tongue, jaws, cheeks, arms, legs, fingers, or toes
• Extensive LMs can be associated with venous malformations
• Visceral LMs can cause protein‐losing enteropathy and hypoalbuminaemia
• Various rare syndromes, eg, the Gorham–Stout syndrome, a bone disorder characterised by bone loss (osteolysis) associated with proliferation of lymphatic and/or other vessels

• Doppler ultrasound (and sometimes MRI) is the best examination to confirm the cystic nature of this slow‐flow vascular malformation

• Treatment is directed towards the specific symptoms that are apparent in each individual

• Uncomplicated cases lesions can often be observed

• Bacterial infection should be managed with systemic antibiotics and analgesia 

• For problematic lesions options include:
• Macrocystic lesions can be treated by aspiration followed by sclerotherapy
• Cautery, laser, or radiofrequency ablation can be used to destroy superficial components, but recurrence may occur
• Excision, although recurrence is frequent with microcystic lesions

• The drugs Sildenafil and Sirolimus (rapamycin) have been found successful in some patients