What is Langerhans cell histiocytosis?
Langerhans cell histiocytosis (LCH) happens when part of the immune system stops working the way it should. The term “histiocytosis” comes from the word “histiocyte,” which is a type of white blood cell that is responsible for recognizing and fighting foreign organisms like bacteria that have entered the body. It alerts the rest of the immune system and helps the body mount an immune response.
A Langerhans cell is a type of histiocyte that lives in the skin. Histiocytosis means that there are too many of these histiocyte cells and they do not function normally.
Langerhans cell histiocytosis was previously known as histiocytosis X.
What causes LCH?
LCH is caused by a mutation that happens in white blood cells, causing them to grow and divide when they shouldn’t and this leads to the development of a growth or tumor. The most commonly mutated gene happens in about two of every three cases of LCH and is called BRAF, though other related genes can cause it as well.
LCH isn’t contagious, so you can’t catch it from someone else, and it isn’t hereditary. The mutation in the white blood cell usually happens by chance. There was a debate for a long time about whether LCH was a problem with the immune system or a neoplastic problem like cancer. The discovery of mutations that cause LCH put it more in the neoplastic category, although LCH does not act like a cancer or malignancy in most cases.
Who gets LCH?
LCH can happen in anyone but most often happens in infants and young children. People who smoke are more likely to develop lung LCH.
What are the signs and symptoms of Langerhans cell histiocytosis?
The signs and symptoms of Langerhans cell histiocytosis (LCH) vary depending on what part of the body is affected and how widespread it is. Most of the time, only one area or organ is affected, usually the skin or the bones. However, sometimes the disease can be widespread and affect many organs at once. Some of the signs and symptoms of LCH include:
- Skin: LCH can cause a skin bump or rash similar to eczema, but it doesn’t go away as it usually would with traditional eczema treatment.
- Bone: The cells can collect in a bone, eating away part of the bone and causing swelling and pain. More rarely, cells can infiltrate the bone marrow where the blood cells are made.
- Other organs: LCH can also affect other organs, such as the liver or spleen, which can lead to more serious illness.
- Pituitary gland: It also can affect the pituitary gland, which sits under the brain, leading to a problem called “diabetes insipidus.” Diabetes insipidus is a condition in which there is a lack of the hormone that signals the kidneys to concentrate urine, which causes increased urination and dehydration.
- Lungs: Rarely, LCH can cause large air-filled spaces called cysts to develop in the lungs. They can pop and cause the lung to collapse or they can cause scar tissue to build up in the lungs.
What tests are used to diagnose Langerhans cell histiocytosis?
LCH is diagnosed by doing a biopsy of one of the tissues affected by LCH. A biopsy is a procedure to remove a small piece of tissue and examine it. After the sample is removed, we send the tissue to the lab for a pathologist to examine at under a microscope.
What to expect from the biopsy?
A surgeon or an interventional radiologist performs a biopsy while the patient is asleep, so they don’t experience any discomfort. For a skin biopsy, we apply numbing medicine to the skin, so your child doesn’t feel any pain. We have a skilled team of child life specialists who can talk to your child during the procedure and distract and calm them. The biopsy is usually a simple procedure, which is often done in the outpatient setting.
How do we diagnose LCH?
LCH cells have a specific appearance that makes diagnosis straightforward in most cases. We also perform a genetic test to check to if there is a mutation of the BRAF gene or one of the other genes known to be associated with development of LCH. Once we confirm a diagnosis of LCH, we obtain blood tests, X-rays and other specialized scans to see if it is in other areas of the body, so we can make sure we are treating all of the affected areas and providing the best treatment to cure the patient.
How is Langerhans cell histiocytosis treated?
Langerhans cell histiocytosis (LCH) is treatable and curable in almost all cases. Treatment may include:
- Surgery: Sometimes surgery to remove the lesion is the only treatment a child needs.
- Biopsy: Some children may only need a biopsy, which stimulates the body to get rid of the tumor itself, without any further treatment.
- Topical creams or ointments: Your child’s doctor may recommend these if your child has a skin rash.
- Chemotherapy medicines: If the disease is more widespread, treatment with chemotherapy medicines, given under the direction of a pediatric oncologist, may be necessary.
Treatment is generally given in the outpatient clinic and is usually very well tolerated. For patients whose LCH carries a specific mutation like V600E BRAF, we can use medicines that target that specific mutation. For patients with lung LCH, which is caused by smoking, stopping smoking alone can make it go away. Sometimes the lesions can come back, but there are a lot of different treatments available, and further treatment usually makes it go away. Once cured, patients can go back to their normal life.
Why choose us for treatment of LCH?
While LCH is a rare disease, doctors at Children’s Hospital Colorado treat children and young adults from all over the Rocky Mountain region, so they have a lot of experience treating and curing many different forms of LCH. Specialists in the Center for Cancer and Blood Disorders are members of the Histiocyte Society, which promotes research on understanding more about LCH and developing better treatments. They also collaborate closely with LCH experts from around the world to provide the best, most up-to-date treatments available for LCH.
- The Histiocyte Society is committed to advancing knowledge about histiocytic disorders and improving outcomes for patients through clinical research.
- The Histiocyte Association is a nonprofit organization dedicated to addressing the unique needs of patients and families affected by histiocytic disorders, while also searching for a cure.
- St. Baldrick’s Foundation is a nonprofit organization committed to supporting research to find cures for childhood cancers and give survivors long and healthy lives.
- North American Consortium for Histiocytosis’ mission is to cure all patients with histiocytic diseases and optimize outcomes through innovative and collaborative research.