Donate

I am...

Newly Diagnosed

A Patient or Caregiver

A Researcher

A Healthcare Professional

Pulmonary Langerhans Cell Histiocytosis

Single-system Pulmonary Langerhans cell histiocytosis (PLCH) is an uncommon type of Langerhans cell histiocytosis that affects only the lung. Langerhans cell histiocytosis (LCH) is blood disease which is now recognized as a cancer and can affect virtually any organ system of the body.

Single-system Pulmonary Langerhans cell histiocytosis (PLCH) is an uncommon type of Langerhans cell histiocytosis that affects only the lung. Langerhans cell histiocytosis (LCH) is blood disease which is now recognized as a cancer and can affect virtually any organ system of the body. Lung involvement in LCH can occur alone (single-system PLCH) or as multi-system disease (where it involves more than one organ system). PLCH is unique in that it has a strong association with smoking (over 95% cases) and many cases can resolve by quitting smoking. It is believed that cigarette smoke attracts specific immune cells in the lungs (Langerhans cells) which leads to a cascade of inflammation and injury to the air passages and lung tissue over time. PLCH causes the formation of multiple lung cysts (air-filled pockets inside the lung tissue), which can progress over time leading to loss of lung function.

The exact prevalence of single-system Pulmonary Langerhans cell histiocytosis (PLCH) is unknown. Current estimates suggest that there are between 25,000 – 50,000 patients with PLCH worldwide, however, these numbers are likely an underestimate.

The information on this page has been written and reviewed by the Histiocytosis Association Board of Trustees Scientific Committee and a member of the Histiocyte Society, and subsequently audited by patients and families to ensure enough information was captured. The most recent update to this page was in January of 2025.

Latest PLCH Educational Webinars

Pulmonary Hypertension in Pulmonary Langerhans cell histiocytosis

Focus on Adult LCH/PLCH

Is single-system PLCH a cancer?

Recently, cells from LCH tumors (lesions) were found to have cancer-causing DNA changes (mutations); these include mutations of the BRAF, MAP2K1, and ARAF genes. Previously thought to be an auto-immune disorder, LCH was classified as a blood cancer in 2008 by the World Health Organization. Recently, cancer-causing mutations in the BRAF- and other genes have also been found in cases with single-system PLCH, suggesting that a large proportion of these may be cancerous, driven by underlying inflammation from smoking.

What is the natural history and prognosis of single-system PLCH?

The natural history of PLCH is variable. In general, PLCH is a progressive disease and leads to a gradual decline in lung function over time. Smoking cessation can lead to complete reversal of single-system PLCH especially in the early stages (nodules). The inability to stop smoking is associated with a worse prognosis and can accelerate the loss of lung function leading to destruction of air passages and lung tissue in the form of cysts and fibrosis. Progressive PLCH can impair the oxygenation of lungs, resulting in increased pressure in the blood vessels of the lungs called as pulmonary hypertension. Single-system PLCH rarely spreads to other organs outside the lungs, but any new symptoms should prompt further investigations into additional sites of disease.

Symptoms

PLCH affects patients in different ways. The most frequently reported symptoms include shortness of breath, dry cough, sinus congestion in the early stages, and low oxygen levels in the blood in the advanced stages. Some individuals with single-system PLCH may have little to no symptoms at all.

Rarely, PLCH can cause collapse of the lung called as pneumothorax, which often requires an urgent procedure to expand the lung by using tubes or needle. The common symptoms of a pneumothorax include sudden onset chest pain and shortness of breath, typically more on one side.

About 10-15% of adults with PLCH will also have symptoms due to disease in organs outside of the chest, for example bone pain or skin rash.

Diagnosis and Treatment

Diagnosis of single-system PLCH:

The most important diagnostic test in patients with suspected single-system PLCH is a CT scan of the chest (CAT scan). In many patients, the CT scan may show changes that are highly suggestive of PLCH (the presence of cysts and/or nodules), and mostly in the upper and middle parts of the lungs. In many cases, there is a need to obtain a lung biopsy so it can be reviewed under the microscope to confirm the diagnosis and also allow for testing of BRAF and other cancer-causing mutations. Other tests (blood work, ultrasound of the abdomen, PET scan, MRI brain) may be indicated in some patients to understand the extent of disease and whether there is LCH affecting organs other than the lung. Tests to assess the function of the lung (pulmonary function tests) or effects on the heart (echocardiogram) are usually conducted.

 

What is the treatment for single-system PLCH?

Stopping smoking in any form (including marijuana, vaping, and eliminating second-hand smoke exposure) is key to the management of PLCH. Treatment options for individuals whose PLCH does not improve after successful smoking cessation include consideration of certain chemotherapy medications or targeted therapies. It is therefore important for the lung doctors (pulmonologists) to collaborate with cancer doctors (hematologists/oncologists) to treat such cases. Other medical therapies that may be used for advanced-stage PLCH include therapies for pulmonary hypertension and oxygen for selected patients.

Since cigarette smoking is also a common cause of other serious conditions (heart attack, emphysema or chronic obstructive pulmonary disease [COPD], lung cancer), it is critical to manage these conditions in individuals with PLCH to improve survival. Many individuals with single-system PLCH struggle with symptoms of chronic pain, fatigue, anxiety, and depression, which should be managed adequately alongside.

Other medical therapies that may be used to treat PLCH include therapies for pulmonary hypertension (a condition associated with elevated pressures in the lung circulation) and oxygen for selected patients. Because of the high risk of recurrence, patients with PLCH who develop a pneumothorax should undergo procedures such as pleurodesis (remove of excess fluid from the area between the lungs and chest wall) in order to prevent/reduce the risk of future pneumothoraxes.

There are several BRAF inhibitors (vemurafenib, dabrafenib, and encorafenib) and MEK inhibitors (cobimetinib, trametinib, binimetinib, selumetinib). The BRAF inhibitors are given for histiocytosis with the BRAFV600E mutation, and the MEK inhibitors are given in many different instances, including (1) cases of mutations in the MAPK pathway other than BRAFV600E (2) cases where no mutation has been identified and (3) for BRAFV600E mutations as well. In some instances of histiocytosis with BRAFV600E mutation, combined BRAF and MEK inhibitors are given. Which specific inhibitor medication (i.e. cobimetinib versus trametinib) a physician may administer can depend on several factors, such as (1) the amount of evidence that exists for a particular medication for a specific disease or age group (2) the experience of the physician administering a particular medication and (3) possible drug interactions between the inhibitor and an individual’s other medications.

The care of patients with PLCH is often provided by pulmonologists, although sometimes a multi-disciplinary approach with input from other specialists like a hematologist/oncologist or dermatologist may be necessary, depending on which organs are involved.

To learn more about Langerhans cell histiocytosis (LCH), including more information on treatment options to multisystem Pulmonary Langerhans cell histiocytosis (PLCH), click here. You can also give us a call at +1-856-589-6606 or email us at info@histio.org.

FAQ

PLCH (pulmonary Langerhans cell histiocytosis) is LCH of the lung. It affects mostly adults who smoke and often occurs without other LCH involvement.

The exact prevalence of PLCH is unknown. Current estimates suggest that there are between 25,000 – 50,000 patients with PLCH worldwide. These numbers are likely an underestimate.

The care of patients with PLCH is often provided by pulmonologists, although sometimes a multi-disciplinary approach with input from other specialists like a hematologist/oncologist or dermatologist may be necessary, depending on which organs are involved.

Side effects include:

  • Low blood counts (with higher risk of infection).Mild nausea/vomiting/constipation
  • Easily sunburned
  • Skin irritation at site of injection
  • Thin or brittle hair
  • Fatigue
  • Bone pain
  • Hoarseness
  • Seizures
  • Shortness of breath
  • Nerve damage (especially in adults) with tingling, numbness and/or pain of the hands and feet

Side effects include:

  • Increase in blood sugar
  • Increase in appetite
  • Heartburn
  • Bloating/fluid retention/weight gain
  • Difficulty sleeping
  • Mood/behavior/personality changes
  • Higher risk of infection
  • Slow wound healing
  • Muscle weakness
  • Loss of bone calcium
  • Increased hair growth

More unusual side effects may include:

  • Problems with vision/eye pain
  • Seizures
  • Confusion

Side effects include:

  • Mouth sores/swollen, tender gums
  • Nausea/vomiting/diarrhea/decreased appetite
  • Low blood counts
  • Dizziness/drowsiness
  • Headache

More unusual side effects may include:

  • Blurred vision or loss of vision
  • Seizures
  • Confusion
  • Weakness/difficulty moving one or both sides of the body
  • Loss of consciousness
  • Lung damage
  • Allergic reactions

More common signs/symptoms include:

  • Low blood counts (red cells, white cells, and clotting cells)
  • Nausea/vomiting/decreased appetite
  • Headache
  • Weakness/fatigue/achiness
  • Rash/darkening of the skin

More common signs/symptoms include:

  • Flu-like symptoms (Fever, chills, headache, fatigue, nausea/vomiting)
  • Decreased appetite
  • Constipation
  • Low blood counts (red cells, white cells, and clotting cells)
  • Skin rash/redness/itching

Articles and Links

Articles

Links

Histiocytic Disorders Overall FAQ

Histiocytic disorders are a diverse group of diseases caused by over-production of white blood cells known as histiocytes, which can lead to organ damage and tumor formation. They include a wide variety of conditions that can affect both children and adults.

The disorders are classified into three groups based on the types of histiocyte cells involved.

  • The first group is called a dendritic cell disorder, and the most common disease in this group is Langerhans cell histiocytosis. Also included in this group are more rare diseases, juvenile xanthogranuloma (JXG) and Erdheim Chester.
  • The second group is called a macrophage cell disorder, and includes primarily hemophagocytic lymphohistiocytosis (HLH) and Rosai-Dorfman.
  • The third group is called malignant histiocytosis and includes certain kinds of leukemia and tumors.

All of the diseases are caused by the over-production of white blood cells called histiocytes. Their different classifications depend on the type of histiocyte involved.

The Histiocytosis Association’s online community provides a number of informational documents and articles, as well as links to medical articles about the histiocytic disorders. While the Internet does provide a significant volume of information about histiocytic disorders, some of this information is not accurate. It is important to look for documents that are current, are free of grammatical and spelling errors, appear to be objective, are free of advertisements, and clearly state their sources.

Histiocytosis is a rare disease that is caused by the over-production of a type of white cell that can lead to organ damage and the formation of tumors. The Histiocytosis Association’s Disease Fact Sheets are also a great way to help explain these complicated diseases to family and friends.

According to the Rare Disease Act of 2002, an orphan disease, also known as a rare disease, affects less than 200,000 persons in the U.S., or less than 1 in 1500 people. The criteria may vary in other countries. For example in Europe, an orphan disease is defined to occur in less than 1 in 2000.

According to the National Institutes of Health there are approximately 6800 such diseases. Combined, they affect nearly 30 million Americans.

What Do I Do Now?

A new diagnosis of a histiocytic disorder can bring feelings of being overwhelmed, bewildered, scared, angry, sad, disappointed, helpless, and sometimes even feelings of guilt. It is a time filled with unknowns, change, and new people and situations. Most parents feel ill-equipped to understand what is happening to their child and how to navigate through the illness to recovery. There are, however, strategies and resources that can help you, your child, and other family members get through the uncertain times that lie ahead. One step at a time, you can gather information, create a support system, learn how to cope with stress, and become a strong advocate for your Histio Warrior as part of the medical team. The following tips and suggestions are provided to help guide you through this journey toward your Histio Warrior’s good health.

Histiocytosis can be considered a systemic illness; especially in cases where the disease is found in more than one system within the body. Some patients and caregivers may prefer to consult several specialists, depending on the different locations of symptoms. In this case, it is helpful to have one physician coordinate your care. An oncologist is usually the most appropriate choice.

Make sure that your doctor is someone you can trust and with whom you can communicate. Important qualities to look for in a doctor are:

  • feeling as though you are heard,
  • being given the opportunity to ask questions, and
  • feeling respected.

If you are unsure about your physician, it is reasonable to schedule another appointment to discuss your concerns. While it is ideal to find a physician experienced and knowledgeable about histiocytic disorders, it is not always possible to find one who is nearby. If this is the case, ask the physician if he/she is open to a consultation with a knowledgeable physician and is willing to learn more about the disease. The Histiocytosis Association maintains a listing of doctors in a Physician Finder who have are knowledgeable about histiocytosis. You may also call us at +1 856-589-6606 for help finding other physicians in your area or for more information.

Call your insurance company to find out whether your plan will cover visits to the physician you are considering. Oftentimes a Team Social Worker and/or the hospital financial counselor can help smooth out insurance problems. Ask for help from a trusted friend if you feel overwhelmed in dealing with insurance issues.

Talking with your child: If your child is old enough to understand, sharing information can help him/her build trust in both you and his/her/your medical caregivers. It can also help your child cooperate with treatment and become a part of his/her/your medical team.

  1. Use words and ideas that are appropriate for your child’s age.
  2. Share information at a level that is in keeping with his/her ability to understand.
  3. Use your child’s questions as a guide to what he/she wants to know.
  4. Encourage your child to talk about his/her fears and concerns.
  5. Remind your child how much you love him/her.

If you are uncertain about how to talk to your child, your healthcare team can be of assistance.

Talking with family and friends: In the days and weeks following diagnosis, extended family and friends will need to be notified and periodically updated. However, explaining your situation multiple times can be exhausting and time-consuming. The Association offers a private Facebook group to help connect you with others. Some patients and families find that journaling is therapeutic and can provide an easy way to track their history and progress.

Talking with your child’s siblings: When your child is diagnosed with a histiocytic disorder, everyone in the family is affected, including brothers and sisters. They may feel anxious, lonely, resentful about the attention their sibling is getting, guilty about being healthy, or even responsible for the illness.

  1. Give information that is appropriate for your child’s age.
  2. Explain that no one did anything to cause the illness, and reassure them that it is not contagious.
  3. Give them a chance to talk about how the illness is affecting them or you. Be willing to answer questions.
  4. Remember that it will be easy for them to feel overlooked and unimportant, so it will be important to show that you love them and are proud of them.

Talking with your child’s school: Contact your school principal/counselor regarding your child’s diagnosis or if your diagnosis may affect your child. You may want to take brochures and other basic information about your histiocytic disorder. If your child is the patient, provide a written description of the health needs, such as what medications may need to be given at school, dosages, and times, signed by your physician. (Some schools will provide the form to be filled out and signed by your child’s physician.) Ask for a plan to take care of your child’s needs at school. You may need to provide written permission for the school to communicate with your physician, in case of an emergency.

Appointments: A calendar is a useful tool for remembering appointments and planning for changes to your established schedule. Calendars that show a week at a time also provide room on each day to record additional brief notes and reminders.

Medical Information: While some basic medical notes can be kept in a calendar, some patients and parents may choose to enter medical information in a laptop or keep a separate notebook. Be sure to date all entries. This information will be especially helpful when a new or different caregiver is involved. Examples that you may want to keep track of include:

  1. Results of various tests.
  2. A listing of allergies.
  3. A listing of medications and dosages.
  4. Names and phone numbers of your medical care team.
  5. Health information, such as your hospital number, social security number, and insurance information.
  6. Records of what was discussed during a medical visit/phone conversation and by whom.
  7. Notation of changing symptoms.

Adults may find it helpful to collect and organize medical records, starting as soon as possible after diagnosis. Although the original reports must remain in the physician or hospital file, you are legally entitled to copies of your records. You must submit a signed request for each physician’s office and the hospital. By keeping all records in one place, you can easily share these with other health care providers that you may see in the future. Follow this link to read more about obtaining your medical records.

If you have health insurance, it’s important that you know what your plan covers. Read your policy carefully to understand the health and medical services covered. Find out the portion of medical expenses you’ll be responsible for paying. When you have questions or there are things you don’t understand, reach out to other experts available to you, such as the human resources personnel at your place of employment or financial counselors at your medical treatment center. If filing and tracking claims feels overwhelming, you may want to ask a trusted friend or relative to assist in managing your insurance issues.

When you call the insurance company, ask to work with one case manager. This may help simplify the process by having one person that knows your needs and can manage your claims. If possible, communicate with the same person on an ongoing basis. Remember to keep a journal of all encounters.

If you don’t have health insurance, if coverage is not adequate, or if you are not able to get insurance because of your pre-existing condition, you may qualify for your state’s high-risk insurance pool. You can obtain more information about whether your state participates at the National Association of State Comprehensive Health Insurance Plans website. If your state does not participate, you may qualify for the federal high-risk insurance pool. For more information, contact the U.S. Department of Health and Human Services.

Online: You can subscribe for our emails and you will receive important announcements regarding the latest information on the histiocytic disorders. The Association also maintains a Facebook page for families and patients with this disease.

Local support: The hospital where you or your child is being treated may have a support group for patients or parents of children with histiocytic disorders, rare diseases in general, or even cancer. Establishing face-to-face relationships with others going through similar experiences can be helpful.

The Association sponsors patient and family Regional meetings, which are held in various locations around the U.S. and hosted by Association staff and volunteers. They are a good opportunity to meet other families and patients, learn from expert physicians, receive and give emotional support, and share practical coping skills while also providing a time to relax, knowing you are with people who understand.

Fundraising events for histiocytic disorders are another way to make connections with families in your region. A listing of dates and fundraising events is provided on the Upcoming Events page.

Virtual opportunities to connect are also available.

Self-education about histiocytic disorders is an important part of advocating for your and your child. It will help you to make informed decisions about care and play a more active role in recovery.

The Association website provides education on a number of topics, including disease information, family resources, and past and ongoing research projects. The Histio Resource Directory provides an extensive listing of global, national, and state-by-state resources for patients and families. Some of the resources listed are informational, while others are service-based. A listing of past and current research projects funded by the Association can be found on the Grant Awards page, providing a glimpse into the past trends and current progress of research into the histiocytic disorders. The Disease Information section of the website features detailed, reliable information on all of the histiocytic disorders. This can be printed out and shared with medical caregivers, family, and friends if needed.

The Internet is a good source of information about histiocytosis and the treatment options, but the amount of information can be overwhelming, and the information is not always reliable. Some of it, in fact, is inaccurate. Reliable information is more likely to be found in more current documents that are free of grammatical and spelling errors, appear to be objective, are free of advertisements, and clearly state their sources.

It is essential to take an active role in your or your child’s health care. However, many patients and caregivers have little experience being advocates when they first receive a rare disease diganosis. The following is a list of essential tips for becoming a successful advocate:

  1. Learn about the diagnosed type of histiocytosis and become acquainted with the basic medical terms. Knowledge is empowerment.
  2. Know the warning signs that mean you may need emergency help.
  3. Know who to call in case of an emergency, and keep phone numbers handy.
  4. Keep a list of healthcare members involved in your medical care, along with contact information.
  5. If possible, take a companion (family member or friend) along on important medical appointments. The companion can help with remembering details of what was said and may assist by taking notes.
  6. Write down your questions before entering appointments or meetings and write down further questions as you think of them during the meeting. Don’t be afraid to ask these questions. This will be an important step in beginning to understand more about the disease. Medical information is often confusing and the language used by medical professionals is not easily understood, especially during stress. Whenever someone uses a word that you don’t understand, stop the conversation for a minute and ask the person to explain.
  7. Keep a healthcare notebook with a listing of allergies, medications, symptoms, and communications with healthcare providers.
  8. Find out about resources that the hospital provides, such as a social worker or patient representative. They can often assist with transportation costs, temporary housing if needed,
  9. parking fees, insurance issues, counseling, and other services.
    Be persistent in getting the care you feel that you or your child needs. Don’t hesitate to ask for what you need, and if you do not feel responded to, ask again or ask someone who will respond.

Trust your intuition. It can be a powerful decision-making tool. You know yourself or your child better than anyone else.

Being sick or caring for a sick child/loved one can be stressful and may take a toll on your physical and emotional health. Recognizing your own needs for support, help, health, and comfort can be difficult when you’re focused on the needs of others, but it’s important to remember that caring for yourself is essential. When your needs are taken care of, your loved ones will also benefit. Give yourself time for regular physical activity and rest. Pay attention to signs of stress, and consult your physician if you need further help.