Doctors at MSK care for more adults with histiocytosis than any other hospital in the United States. They’re also experts in treating histiocytosis in children and teens.

How we treat histiocytosis depends on:

• The type of histiocytosis.
• The location of the disease in the body.
• How many parts of the body are affected.
• How quickly the histiocytosis is growing.

When you come to MSK for histiocytosis treatment, your care team will have many kinds of experts. Together, they talk about your case at regular Tumor Board meetings. They will help you decide on a plan of care just for you, using the best therapies for your needs.

Your care team will also help you manage any side effects of treatment. They support you so you can have the best possible quality of life.

Our doctors may recommend a range of treatments. They include:

• Observation (monitoring) with exams and tests from time to time to check your health.
• Surgery or low doses of radiation therapy to treat skin or bone tumors.
• Chemotherapy and drugs that suppress the immune system.
• Targeted therapies for histiocytosis caused by gene changes (mutations and variants).
• New therapies offered through research studies, also known as  clinical trials.

Surgery

Surgery to remove a tumor may be the only treatment needed when histiocytosis involves only 1 area of the body. Sometimes, part of a tumor can press on an important area, such as the eye. Removing that tumor part can improve symptoms. 

Radiation therapy

Radiation therapy is often used to treat adults with histiocytosis that only affects 1 area. Radiation can work very well on some types of histiocytosis, such as Langerhans cell histiocytosis (LCH).

Radiation is less useful for types of histiocytosis that involve many body areas, such as Erdheim-Chester disease (ECD). Treatment is more likely to include medications. 

Chemotherapy

Chemotherapy (chemo) uses strong drugs to kill cells, or stop or slow their growth. When histiocytosis affects a few areas or grows fast, doctors may use chemotherapy to kill some immune cells.

Common histiocytosis chemotherapy drug treatments are:

• Vinblastine, often combined with prednisone.
• 6-mercaptopurine, which is taken by mouth. It can be used with prednisone and vinblastine.
• Methotrexate, which is given weekly as a pill or an injection into the skin.
• Cytarabine.
• Cladribine (also called 2-CDA) and clofarabine. They’re often used to treat more serious forms of histiocytosis.
• Hydroxyurea.

For kids and teens, we often use mild chemotherapy treatments. This helps stop organs from being harmed over time.

Immunosuppressants 

Immunosuppressant drugs keep the immune system from being too active. These drugs can help with symptoms of histiocytosis.

Here are examples of immunosuppressants to treat histiocytosis:

• Prednisone is very useful for Langerhans cell histiocytosis. It’s a standard therapy when LCH is first diagnosed. It’s often used along with vinblastine and 6-mercaptopurine.
• Interferon-alpha is sometimes used to treat ECD. It’s injected into the skin.
• Anakinra is an immune-suppressing medicine for ECD. It’s injected into the skin and helps with swelling.

Targeted medicines for histiocytosis

Targeted or precision medicines treat histiocytosis by targeting the gene changes (mutations or variants) that cause the disease. About half of people with Erdheim-Chester disease (ECD) and Langerhans cell histiocytosis have a tumor with a mutation in a gene called BRAF. We target this gene mutation with drugs that block it.

MSK has been a leader in developing medications that treat this gene mutation. Our doctors led the clinical trials for a drug called vemurafenib (Zelboraf^®) for the treatment of histiocytosis. Vemurafenib inhibits BRAF.

In November 2022, the FDA approved cobimetinib (Cotellic^®) for treating LCH in adults, ECD, and Rosai-Dorfman disease. This targeted drug is also used to treat melanoma. It blocks a family of proteins called MEK. The clinical trial that led to cobimetinib’s approval for histiocytosis was done at MSK.

Targeted therapies may help children who have histiocytosis that’s hard to cure.

MSK has clinical trials that assess targeted therapies for children. You or your child may be able to join these research studies. Call 833-MSK-KIDS (833-675-5437) or email us at [email protected] to learn more about our histiocytosis clinical trials.

Managing treatment side effects

Histiocytosis treatments can cause side effects. For example, immunosuppressant drugs can raise the chance of getting an infection. Chemotherapy can lower blood counts and raise the chance of infection or bleeding. Targeted therapies can cause side effects such as a rash.

Your care team will talk with you about the possible side effects of histiocytosis treatment. They will support you and help you manage any side effects.

Follow-up care for histiocytosis

After histiocytosis treatment, we will want to see you regularly for follow-up exams for several years or longer. We watch for side effects of treatment that can start any time during or after histiocytosis treatment. We’ll also look for any signs the disease is coming back.

During these check-ups, you may have tests that include:

• Physical exam
• Blood tests
• Biopsies
• Tests to see how your heart is working
• Imaging tests, such as CT and MRI scans

Caring for adolescents and young adults

A child with histiocytosis may no longer need treatment. Or, they may grow into adulthood while living with histiocytosis.

We work closely with MSK’s Adolescent and Young Adult (AYA) Program. It helps teach teens how to take care of their health as they become young adults. We want to be sure there’s a smooth transition from pediatric to adult care.

The team at MSK’s Long-Term Follow-Up Program also provides screening, monitoring, and health advice. They look for any late complications that may come up and make sure your child has the best quality of life possible.

Living beyond histiocytosis

Life after cancer can be filled with changes you did not expect. Our survivorship team is here to lead you through those changes. They will be your guide to living beyond cancer.  

Caring for you after cancer treatment is part of MSK’s focus on supporting the whole person. Our goal is to improve your quality of life before and after your cancer care.  

Our survivorship team has deep experience in helping people who have completed their cancer care. They create a plan for you that focuses on your health and wellness. Our survivorship team treat any problems related to cancer therapy.

Living beyond cancer care

MSK offers resources to help you with the lasting effects of cancer on your body, emotions, and daily life. Your survivorship team expert can help you choose resources that are best for you, including:

• Pain management
• Nutrition
• Exercise
• Integrative medicine therapies
• Skin, nail, and hair health
• Sexual health and fertility

See all of MSK’s Living Beyond Cancer resources.