Erdheim-Chester Disease

Erdheim-Chester disease (ECD) is a very rare blood cancer that can affect several parts of your body. It can cause many different symptoms depending on the organs it affects. ECD is a type of histiocytosis, a condition that causes histiocytes to build up in your tissues. Histiocytes are white blood cells (immune cells) that typically don’t circulate in your blood like other blood cells.

With ECD, abnormal histiocytes multiply uncontrollably and spread to different parts of your body. The abnormal cells cause inflammation that damages your organs. The cells may clump together to form tumors. Without treatment, the disease can cause life-threatening organ failure.

Only 1,500 cases of ECD have been reported since 1930, when healthcare providers first diagnosed it. Experts don’t know the exact number of cases. But, based on recent studies, they estimate that ECD may affect 1 out of 1 million people in the U.S. each year. The disease is most common in adults in their 40s and 50s, but children may have it. Erdheim-Chester disease is more common in men, who account for 7 out of 10 cases.

Symptoms of Erdheim-Chester disease

This disease can cause a wide range of symptoms. Some typical ones are:

• Bone pain: Pain in both legs is the most common symptom. The pain often starts in your knees.
• Abdominal pain: ECD in your kidneys or the back of your belly may also cause lower back pain, painful urination, fatigue, muscle cramps and swelling in your ankles, feet and face.
• Balance issues: This disease can damage tissue in the parts of your brain that manage balance and coordination. Damage to your nervous system can affect the muscles that control speech, so you slur your words.
• Excessive thirst and urination: These are symptoms of diabetes insipidus, which can happen if ECD damages your pituitary gland. ECD can also affect other glands and cause symptoms like feeling cold all the time and gaining weight.
• Fatigue and shortness of breath: ECD may affect your heart, including the fluid-filled sac that surrounds your heart. It can cause swelling in your lower legs, ankles and feet.
• Eye pain and vision issues: This disease may also cause bulging eyeballs, double vision and yellowish growths on your eyelids.

Some people don’t have symptoms. They learn they have ECD when X-rays, CT scans or other imaging tests detect a mass or group of abnormal cells.

Erdheim-Chester disease causes

Scientists believe certain genetic variations (changes) may be one cause. More than half of people with Erdheim-Chester disease have a changed BRAF gene. Changes in the MEK gene may also play a role. These genes manage how fast cells multiply and spread.

With ECD, the genetic changes turn normal histiocytes into abnormal ones that multiply and spread. Researchers continue to look for other genetic variations that may drive this disease.

How doctors diagnose ECD

A healthcare provider will ask about your symptoms and health history. They may do several tests, including:

• Biopsy: Your provider may take a small tissue sample to check under a microscope. They’ll check for ECD signs and test tissue cells for specific changed genes.
• Imaging tests: Certain tests can detect damage in your bones and in soft tissues in organs, like your brain. Your provider may do a bone scan, X-ray, CT scan, PET scan and/or MRI scan.
• Blood tests: Your provider may check your blood for signs of kidney issues, inflammation or changes in hormone levels.

It may take time for your healthcare provider to diagnose ECD. The disease can develop throughout your body and cause many different symptoms. Also, because ECD is a very rare condition, providers may not have much experience with it. This means they may not immediately recognize ECD as the source of your symptoms.

How is Erdheim-Chester disease treated?

There’s no cure for this disease. But new medications are helping people live longer. Healthcare providers may use common cancer treatments, like:

• Targeted therapy: This is medication that focuses on the specific genetic variations that cause ECD. For example, vemurafenib (Zelboraf^®) treats ECD involving BRAF gene variations. Cobimetinib (Cotellic^®) treats ECD involving MEK gene variations. Both medications slow or stop how fast cancer spreads. 
• Immunotherapy: This treatment helps your immune system identify and fight cancer cells more effectively. Interferon-alpha is a common immunotherapy medication for ECD.
• Chemotherapy: These medications keep abnormal cells from spreading. Cladribine (Mavenclad^®) is the most common type of chemotherapy to treat ECD.

Healthcare providers sometimes recommend treatments to help ease symptoms. Those include:

• Corticosteroids: This medication can ease inflammation.
• Surgery: ECD can cause tissue damage and inflammation that affect your organs. For example, inflammation and damaged tissue can block the tubes (ureters) that carry urine from your bladder. You may need surgery to correct this or other issues.

Your provider may recommend a clinical trial if they think you could benefit from newer treatments that are still being studied.

ECD may not cause symptoms. In that case, your provider may recommend active surveillance. You’ll have regular checkups and tests to check on your health.

When should I talk to a doctor?

You’ll have regular follow-up visits so your healthcare provider can check on your progress. They’ll let you know how often you can expect checkups and tests.

ECD can cause different symptoms if it spreads through your body. Let your provider know about any changes you notice.

How long can you live with Erdheim-Chester disease?

People are living longer with ECD, thanks to cancer treatments like targeted therapy and immunotherapy. One recent study estimates that, overall, 8 out of 10 people with ECD are alive five years after diagnosis.

ECD is a complicated disease. It can affect your body in many ways. Ask your healthcare provider to explain what you can expect. They’re your best source of information.

Is there anything I can do to feel better?

Treatments like cancer rehabilitation and palliative care may help you manage issues that ECD can cause. Cancer rehabilitation specialists can help you prepare to start treatment. Palliative care specialists provide support to help you manage ECD symptoms and treatment side effects. Your providers can also connect you with resources for people who have a rare disease.