LCH is an unusual condition. It has some characteristics of cancer but, unlike almost every other cancer, it may spontaneously resolve in some patients while being life-threatening in others.
There has been some controversy about whether LCH is a cancer but it is classed as such and sometimes requires treatment with chemotherapy. LCH patients are therefore usually treated by children’s cancer specialists (paediatric oncologists/haematologists). Most children will recover completely from LCH.
Langerhans refers to Dr Paul Langerhans, who first described the cells in the skin which are similar to the cells found in LCH lesions.
Histiocytosis refers to histiocytes which are cells that are part of the immune system, and are found in many parts of the body.
There are two types of histiocytes:
- Macrophage/monocyte cells - these destroy harmful proteins, viruses and bacteria in the body
- Dendritic cells - these stimulate the immune system
Langerhans cells are dendritic cells and are normally only found in the skin and major airways. In LCH, the abnormal dendritic cells that look similar to Langerhans cells may be found in different parts of the body, including the bone marrow, skin, lungs, liver, lymph glands, spleen and pituitary gland. When these abnormal dendritic cells accumulate in these tissues, they may cause damage.
LCH is divided into two groups:
- Single-system LCH - when the disease affects only one part of the body, for example the skin or the bone
- Multi-system LCH - when it affects more than one part of the body
Causes
We don’t know what causes LCH but there is research going on all the time to try and find out. We do know that LCH cells carry one of a range of mutations (eg. BRAF V600E, MAP2K) that causes these dendritic cells to act in an abnormal way, causing LCH. It is not yet clear why and how this mutation occurs but this discovery provides us with potential targets for new experimental therapies. These mutations are not present in the cells of the rest of the body and are therefore not passed on in families.
Signs and symptoms
The symptoms of LCH will depend on which part of the body is affected and whether the disease is affecting more than one part of the body. Some common symptoms are:
- bone pain
- swelling and lumps on the skull
- skin rash such as cradle cap or nappy rash
- discharge from the ear
- hearing problems
- enlarged lymph glands
- irritability
- poor appetite
- breathing difficulties
- tummy problems such as diarrhoea
- liver problems including jaundice
In 10–20% of patients with multi-system disease, the pituitary gland at the base of the brain is affected, causing hormonal problems. This can lead to passing larger amounts of urine and being very thirsty. This is called ‘diabetes insipidus’, which is different from ‘diabetes mellitus’ (sugar diabetes) and can be well-controlled with specific medicines. Occasionally, other pituitary hormones may be affected, causing poor growth or delayed puberty, which can also be treated.
How LCH is diagnosed
A variety of tests and investigations may be needed to diagnose LCH. Tests are likely to include the removal of a sample of cells from an affected part of the body (a biopsy). This is usually done in an operation under a general anaesthetic. The cells are then examined under a microscope. X-rays are taken of the bones, skull and lungs. Blood and urine tests will also be done.
Additional scans and tests may be required depending on which parts of your child’s body are affected. These tests help the doctors decide whether the disease is a single-system or multi system type.
When your child is having the tests, they may need to stay in hospital. Any tests and investigations that your child needs will be explained to you.
Treatment
Single-system LCH may disappear without any treatment but some patients do require treatment. Surgery, corticosteroids and oral indomethacin are some of the treatments used in single-system LCH. Multi-system LCH (and some single-system LCH) is treated with chemotherapy with or without corticosteroids.
Chemotherapy is anti-cancer medication that can destroy cancer cells, and corticosteroids are hormonal substances that are naturally produced in the body. Both chemotherapy and corticosteroids can help to destroy the LCH cells.
Treatment with drugs inhibiting specific, disease-causing mutations in LCH cells may be considered in a small number of children with high risk disease, who do not respond to standard treatment and those with rare complications. These drugs are known as BRAF inhibitors or MEK or MAPK inhibitors.
Your child’s treatment will depend on the type of the disease. Your child’s doctor will discuss the treatment options with you.
Clinical trials
Many children have their treatment as part of a clinical research trial. Clinical trials are carried out to try to improve our understanding of the best way to treat an illness, usually by comparing the standard treatment with a new or modified version. Clinical trials mean there are now better results for curing children’s cancers compared with just a few years ago.
Your child’s medical team will talk to you about taking part in a clinical trial and will answer any questions you have. Taking part in a research trial is completely voluntary, and you’ll be given plenty of time to decide if it’s right for your child. You may decide not to take part, or you can withdraw from a trial at any stage. You will then receive the best standard treatment available.
National treatment guidelines
Sometimes, clinical trials are not available for your child’s tumour. In these cases, your doctors will offer the most appropriate treatment, using guidelines which have been agreed by experts across the UK. Children’s Cancer and Leukaemia Group (CCLG) is an important organisation which helps to produce these guidelines.
Follow-up care and monitoring
Once treatment has finished, the doctors will monitor your child closely with regular appointments to be sure that the LCH has not come back and there are no complications.
LCH sometimes comes back and your child may need treatment again. If this happens, treatments for LCH that have worked for them before may be effective again. The same or different treatment may be required.
After some time, your child will not need to visit the clinic so often, but will continue to be monitored for possible permanent consequences of the disease (e.g. a low production of certain hormones, hearing problems) and may need treatment for these conditions.
Months or years later, some children may develop late side effects from the treatment they have had but this is less common with the medicines used for LCH. You can find more information in our life after childhood cancer resources.
Your child’s doctor or nurse will talk to you about any possible late side effects and will keep a close eye on possible long-term side effects in follow-up clinics.
If you have specific concerns about your child’s condition and treatment, it’s best to discuss them with your child’s doctor, who knows the situation in detail.
Useful LCH links
Histiocytosis Association
www.histio.org
International partnership of patients, families, physicians and friends, which aims to promote scientific research and education related to histiocytosis.
Histio UK
www.histiouk.org
Dedicated to supporting patients and their families, raising awareness of histiocytic disorders and funding research to find a cure. It also publishes the ‘Langerhans Cell Histiocytosis (LCH): A Parent’s Guide’.