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Kaposiform lymphangiomatosis
KLA involves malformations of the lymphatic system, which can affect multiple organs. It is typically caused by changes in certain genes that occur after conception, leading to a wide range of symptoms depending on the areas affected.
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Overview
Kaposiform lymphangiomatosis (KLA) is a very rare and complex condition affecting the lymphatic system. This system is a network of vessels and organs that helps to maintain fluid balance in the body and plays a crucial role in immune function. In KLA, there is an overgrowth of abnormal lymphatic vessels, which can infiltrate and damage surrounding tissues and organs [PMID:33671203]. This can lead to a variety of symptoms, making KLA challenging to diagnose and manage. The condition is not inherited in the typical sense; instead, it usually arises from genetic changes that happen early in development after conception.
KLA can affect individuals of any age, but it is often diagnosed in childhood. Due to its rarity and variable presentation, KLA is sometimes misdiagnosed as other lymphatic disorders. It is distinct from kaposiform haemangioendothelioma, despite sharing some clinical features and treatment approaches.
Symptoms & clinical features
The symptoms of Kaposiform lymphangiomatosis depend heavily on which parts of the body are affected by the abnormal lymphatic growth. These lymphatic malformations can occur in almost any organ system, including the skin, soft tissues, bones, lungs, abdominal organs, and even the brain [PMID:33671203].
Common symptoms can include swelling (lymphoedema), pain, and recurrent infections in affected areas. If the lungs are involved, individuals may experience breathing difficulties, coughing, and chest pain. Abdominal involvement can lead to problems with digestion, fluid accumulation in the abdomen (ascites), and gastrointestinal bleeding. Bone involvement might cause pain, fractures, or bone deformities. In some cases, KLA can be associated with a bleeding disorder called Kasabach-Merritt phenomenon (KMP), which involves low platelet counts and problems with blood clotting [PMID:27025828].
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Affected organs
KLA can affect a wide range of organs and body systems. The lymphatic malformations can be localised to a single area or spread throughout the body (multi-organ involvement). Frequently affected areas include the skin and soft tissues, particularly in the limbs or trunk, leading to visible swelling and masses.
Internal organs often impacted by KLA include the lungs, leading to respiratory complications, and the abdominal organs such as the spleen, liver, and intestines, which can cause digestive issues or internal bleeding. Bones may also be involved, potentially resulting in structural weakness. The heart and central nervous system are less commonly affected but can lead to severe complications if involved.
Risks & severity
The severity of Kaposiform lymphangiomatosis varies significantly among individuals. Some people may have mild, localised forms of the condition, while others experience widespread and aggressive disease with severe complications. The extent of lymphatic involvement and the presence of Kasabach-Merritt phenomenon are key factors influencing severity.
KLA is considered a serious condition, particularly when vital organs like the lungs are affected, as this can lead to life-threatening respiratory failure. The age of onset can also vary; while often diagnosed in childhood, KLA can present at any age. Due to its rarity, exact prevalence figures are not well established, but it is known to be an extremely rare disorder.
Genetic causes
Kaposiform lymphangiomatosis is typically caused by genetic changes in specific genes, most commonly NRAS. These genetic alterations are not inherited from a parent but instead arise spontaneously in a single cell during early development, a phenomenon known as a 'somatic' or 'mosaic' mutation [PMID:33671203]. This means that only some of the body's cells carry the genetic change, and the affected cells are usually found within the lymphatic malformations themselves.
The NRAS gene provides instructions for making a protein involved in cell signalling pathways that control cell growth, division, and specialisation. This protein acts like a molecular switch, turning on or off various cellular processes in response to signals from outside the cell. Pathogenic variants in NRAS can lead to the protein being 'always on', promoting uncontrolled cell growth and proliferation, which results in the abnormal lymphatic vessel development seen in KLA.
- NRAS NRAS proto-oncogene, GTPaseThe NRAS gene provides instructions for a protein called N-Ras, central to regulating cell division, differentiation, and relaying signals within cells.
Inheritance pattern
Kaposiform lymphangiomatosis is not typically inherited from a parent. Instead, it is considered a 'somatic' or 'mosaic' condition. This means that the genetic change responsible for KLA occurs randomly in a single cell during a person's early development after conception.
Because the genetic change is somatic, it is usually only present in the affected tissues or a proportion of cells, rather than in every cell of the body. This means that individuals with KLA generally do not pass the condition on to their children. For relatives, the risk of also having KLA is typically not increased compared to the general population.
Diagnosis & testing
Diagnosing Kaposiform lymphangiomatosis typically involves a combination of clinical evaluation, imaging studies, and sometimes a biopsy of the affected tissue. Imaging techniques such as MRI (Magnetic Resonance Imaging), CT (Computed Tomography) scans, and ultrasound are crucial for identifying the extent and location of the lymphatic malformations [PMID:33671203].
Confirmation of KLA often involves genetic testing, usually performed on a tissue sample from the affected area (biopsy). This type of testing looks for the specific somatic genetic changes, such as in the NRAS gene, that are characteristic of KLA. In the UK, genetic testing for rare and complex conditions like KLA would typically be arranged through an NHS Genomic Medicine Service (GMS) pathway, following a referral to a clinical genetics service. The relevant R-code for genomic testing would be determined by the clinical geneticist based on the patient's specific presentation.
Management & lifestyle
The management of Kaposiform lymphangiomatosis is complex and highly individualised, depending on the location and extent of the lymphatic malformations and the severity of symptoms. Management often involves a multidisciplinary team, including specialists such as paediatricians, oncologists, haematologists, interventional radiologists, and clinical geneticists.
Treatment approaches can include medications aimed at reducing the size and activity of the malformations, such as mTOR inhibitors or targeted therapies that block the activated cell signalling pathways [PMID:27025828]. In some cases, interventional procedures like sclerotherapy (injecting a substance to shrink the vessels) or surgical removal of localised lesions may be considered. Supportive care for symptoms like pain, swelling, and bleeding is also crucial. Regular monitoring is essential to track disease progression and manage potential complications.
UK care pathway
In the UK, individuals suspected of having Kaposiform lymphangiomatosis would typically be referred by their GP or another specialist to a clinical genetics service within the NHS Genomic Medicine Service (GMS). This service specialises in diagnosing and managing rare genetic conditions.
A clinical geneticist or genetic counsellor would assess the patient, discuss the potential for genetic testing (often using a specific R-code for genomic testing on affected tissue), and provide information and support. Genetic counsellors play a vital role in explaining the condition, its inheritance patterns (in this case, somatic), and the implications for the individual and their family, ensuring access to appropriate NHS care pathways.
Frequently asked questions
Is Kaposiform lymphangiomatosis a type of cancer?
No, Kaposiform lymphangiomatosis is not a cancer. It involves the abnormal growth of lymphatic vessels, which can be aggressive and infiltrate tissues, but it is not typically considered a malignant tumour that spreads in the way cancer does.
Can Kaposiform lymphangiomatosis be inherited by my children?
KLA is typically caused by somatic genetic changes, meaning they occur after conception and are not usually passed down from parents to children. Therefore, the risk of passing KLA to your children is generally not increased.
What kind of doctors treat Kaposiform lymphangiomatosis?
Because KLA can affect many parts of the body, a team of different specialists usually manages it. This team might include paediatricians, clinical geneticists, haematologists, oncologists, interventional radiologists, and surgeons.
Is there a cure for Kaposiform lymphangiomatosis?
Currently, there is no single cure for KLA. Treatment focuses on managing symptoms, reducing the size and activity of the lymphatic malformations, and preventing complications. Management plans are highly individualised and may involve medication, interventional procedures, or surgery.
What is Kasabach-Merritt phenomenon?
Kasabach-Merritt phenomenon (KMP) is a rare and severe complication sometimes seen with KLA. It involves a rapid drop in platelet count (cells that help blood clot) and other clotting factor problems, which can lead to significant bleeding issues.
References
- Alkhulaifat D, Ramirez-Suarez KI, Otero HJ. Complex lymphatic anomalies. Pediatric radiology. 2025. PMID: 39853393
- McDaniel CG, Adams DM, Steele KE. Kaposiform lymphangiomatosis: Diagnosis, pathogenesis, and treatment. Pediatric blood & cancer. 2023. PMID: 36683202
- Trenor CC 3rd, Chaudry G. Complex lymphatic anomalies. Seminars in pediatric surgery. 2014. PMID: 25241096
- Agarwal D, Naranje P, Gupta N. Case 343: Kaposiform Lymphangiomatosis. Radiology. 2025. PMID: 41288485
- Lan Y, Zhou J, Qiu T. Refractory kaposiform lymphangiomatosis relieved by splenectomy. Frontiers in pediatrics. 2023. PMID: 37664553
- Ozeki M, Nozawa A, Kawamoto N. Potential biomarkers of kaposiform lymphangiomatosis. Pediatric blood & cancer. 2019. PMID: 31207041
- Ji Y, Chen S, Peng S. Kaposiform lymphangiomatosis and kaposiform hemangioendothelioma: similarities and differences. Orphanet journal of rare diseases. 2019. PMID: 31277673
- Bassi I, Jabali A, Levin L. A high-throughput zebrafish screen identifies novel candidate treatments for kaposiform lymphangiomatosis (KLA). The Journal of experimental medicine. 2025. PMID: 40838953