Depending on the extent of the disease, our doctors may recommend a range of treatments. Targeted therapies are available for people whose disease is caused by certain gene mutations. Surgery or low doses of radiation therapy may be needed to treat skin or bone tumors caused by histiocytosis.

Our team of histiocytosis experts will work to provide the best outcome for your condition. We will help you manage the side effects of treatment and maintain the best possible quality of life. A variety of specialists treat the diseases, depending on the symptoms and which parts of the body are affected.

Many people treated for histiocytosis at MSK join clinical trials of new medications for histiocytosis. Others may be treated with medications outside of a trial. These may include gene-targeting treatments, chemotherapy, or other treatments.

There are several treatments for histiocytosis. Which treatment or combination of treatments is used depends on the individual’s medical history and where the disease is located.

In certain cases, histiocytosis can be observed without treatment.

Surgery

Sometimes histiocytosis involves only one area of the body. This may be a particular bone, for example. In these cases, removing the tumor is the only treatment needed.

In other cases, removing a part of a tumor that is pressing on an important area, such as behind the eye, can improve symptoms. This may allow for other treatments to address the remaining disease.

Radiation Therapy

Radiation therapy can be extremely effective for certain types of histiocytosis, especially Langerhans cell histiocytosis. Radiation is often recommended to treat people whose histiocytosis is affecting only one area of the body. It is considered less effective for other forms of histiocytosis that tend to involve many areas of the body, such as Erdheim-Chester disease.

Immunosuppressants and Chemotherapy

Several medications may be used for different forms of histiocytosis.

• Methotrexate is a chemotherapy medication that has been used for many different histiocytic diseases. It is given weekly as a pill or injection into the skin.
• 6-mercaptopurine is a chemotherapy medication used to treat some types of histiocytosis, in particular Langerhans cell histiocytosis. It is taken by mouth daily for a few weeks. It can be combined with prednisone and vinblastine.
• Hydroxyurea is a chemotherapy pill that has been effective in some kinds of Langerhans cell histiocytosis.
• Vinblastine is a chemotherapy given through an IV. It is used primarily for Langerhans cell histiocytosis. It is often combined with the steroid medication prednisone.
• Prednisone is a type of corticosteroid medication used for many diseases. It is a very effective therapy for Langerhans cell histiocytosis and is part of the standard therapy when that condition is newly diagnosed. It is frequently combined with vinblastine and 6-mercaptopurine.
• Cytarabine is a chemotherapy given through an IV. It is used for Langerhans cell histiocytosis and other histiocytic diseases.
• Cladribine, which is also called 2-CDA, and clofarabine are chemotherapies given through an IV. They are used for many histiocytic diseases, often to treat the more severe forms of disease.
• Interferon-alpha is a medication that is injected into the skin. It is both a chemotherapy and an immunosuppressive medication. It is sometimes used to treat Erdheim-Chester disease. Some people, but not all, experience difficult side effects from this medication.
• Anakinra is an immune-suppressing medicine given for Erdheim-Chester disease. It is injected into the skin once a day.

Targeted Medications for Histiocytosis

Targeted or precision medicines treat histiocytosis by addressing specific gene mutations that cause the disease. About half of people with Erdheim-Chester disease (ECD) and Langerhans cell histiocytosis have a mutation in a gene called BRAF in their tumor. This gene mutation can be targeted with drugs that block it.

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

Clinical trials are underway that are looking at the use of other targeted drugs for treating histiocytosis with BRAF mutations in adults.

Mutations in several other genes have been found in many other histiocytic diseases. These genes include NRAS, KRAS, ARAF, MAP2K1, and MAP2K2. These mutations can also be targeted with precision drugs. Some studies have shown promising results for medications called MEK inhibitors in histiocytosis that does not have a BRAF mutation.

Our doctors review the details of the disease for each person we care for to determine whether a targeted therapy or other treatments, like chemotherapy, are best.