What are the symptoms? LMs cause soft lumps. There is a very wide range from tiny almost undetectable lumps to enormous ones. They are usually slow-growing and may spontaneously resolve or reduce in size. Rapid growth does occasionally occur if there is internal bleeding into the LM or if there is a complicating infection. Depending on the location of the LM, they may cause difficulty with eating and breathing. What are the causes? LMs are congenital (present from birth) and occur due to failure of the lymphatic channels to connect with the main lymphatic system of the body. How is it diagnosed? If the LMs are large they may be detected on prenatal ultrasound. If noted after birth, the diagnosis is on clinical basis. Ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) scans are done to confirm the diagnosis and plan the management of the LM. How is it treated? Small LMs may not require any specific treatment except to wait and see how they develop. Larger ones that continue to grow may need to be actively treated. Large LMs present at birth may necessitate a tracheostomy to help with breathing if there is pressure on the airway – though this is rare. Laser treatment of LMs in the mouth can help to reduce their bulk to assist with eating. Surgical removal of LMs in either the mouth or neck has good results. Injecting attenuated (modified so it does not cause infection) bacteria into the LM can help to reduce size by causing a sclerosing reaction (hardening of tissue). Inheritance patterns and prenatal diagnosis Inheritance patternsNone. Prenatal diagnosisIn some cases, the condition has been diagnosed through ultrasound scanning while in others it has remained undetected. This is because there is a wide variation in the extent to which LMs range in size – from a small growth on the neck to a very extensive mass of growths. Is there support? Cystic Hygroma and Lymphangioma Support Group (CHALSG) Tel: 07770 934 588Email: firstname.lastname@example.orgWebsite: chalsg.org.uk The Group is a non-profit organisation that provides support to children and their parents, and adults with lymphatic malformations (Cystic hygroma or lymphangioma). It offers a support network so that families and individuals can speak to and meet others with the condition. Group details last updated September 2015.