Mastocytosis is a term that describes a group of disorders that are caused by the presence of too many mast cells in the body. Mast cells are a type of blood cell made in the bone marrow that are involved in allergic reactions and fighting parasitic infections. Mast cells produce histamine, a chemical that can cause itching, sneezing, congestion, swelling, and wheezing. Mast cells can be increased in association with some non-cancerous conditions. Sometimes, there are also cancers that may result from the growth of abnormal mast cells.
There are two general forms of mastocytosis: cutaneous and systemic.
Cutaneous mastocytosis
Cutaneous mastocytosis is an increase of mast cells in the skin and accounts for about 90% of mastocytosis cases. Subtypes of cutaneous mastocytosis include:
Urticaria pigmentosa. The most common form of the cutaneous mastocytosis subtypes, urticaria pigmentosa, is characterized by tan or red-brown spots (lesions) on the skin. These spots generally appear first on the midsection of the body, and then spread rapidly throughout the body; such symptoms as nausea, vomiting, and diarrhea may also be present with urticaria pigmentosa.
Solitary mastocytoma. More common in infants and children than in adults, this type usually forms a large nodule (3 centimeters (cm) to 4 cm in diameter) on the arm or leg.
Diffuse erythrodermic mastocytosis. Found most commonly in children younger than three years old, diffuse erythrodermic mastocytosis may not be apparent at birth, but can later appear as rapid thickening of the skin. Symptoms of systemic mastocytosis (see below) and blisters are common.
Telangiectasia macularis eruptiva perstans. This type of cutaneous mastocytosis is found mostly in adults. It is characterized by lesions that do not itch and are smaller than those of urticaria pigmentosa.
Systemic mastocytosis
Systemic mastocytosis involves internal organs throughout the body, including the gastrointestinal tract, bone marrow, liver, spleen, and lymph nodes. In 85% of people with systemic mastocytosis, the cutaneous mastocytosis subtype of urticaria pigmentosa developed first. The risk of developing systemic mastocytosis increases with age. Depending on the number of mast cells in the different organ parts, it is classified as either indolent or aggressive mastocytosis. As the number of mast cells build up in an organ, symptoms of the disease worsen.
Systemic mastocytosis can also turn malignant (cancerous). The risk of systemic mastocytosis becoming cancerous is 7% when disease begins in childhood, and as much as 30% in adults. Mast cell leukemia involves the blood, while mast cell sarcoma involves the soft tissues.
Statistics
Mastocytosis is a rare disorder, and its true incidence rates are unknown.
Cancer statistics should be interpreted with caution. Estimates are based on data from thousands of cases in the United States, but the actual risk for a particular individual may differ. It is not possible to tell a person how long he or she will live with mastocytosis. Because survival statistics are measured in five-year intervals, they may not represent advances made in the treatment or diagnosis of this disease.
A risk factor is anything that increases a person’s chance of developing a disease. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of mastocytosis, most do not directly cause the disorder. Some people with several risk factors never develop the disorder, while others with no known risk factors do. However, knowing your risk factors and communicating them to your doctor may help you make more informed lifestyle and health-care choices.
The following factors may raise a person’s risk of developing mastocytosis:
Age. Most cutaneous mastocytoses appear during infancy and early childhood. The risk of developing mastocytosis also increases during middle age.
C-kit receptor mutation. The c-kit receptor is a protein on the surface of some cells that binds to stem cell factor (a substance that causes certain types of cells to grow). A mutation of c-kit may cause some types of mastocytosis.
People with mastocytosis may experience the following symptoms. Sometimes, people with mastocytosis do not show any of these symptoms. Or, these symptoms may be similar to symptoms of other medical conditions. If you are concerned about a symptom on this list, please talk with your doctor.
General symptoms:
Hives
Red, itchy rash
Diarrhea
Abdominal pain
Fainting
Shortness of breath
Wheezing
Psychologic changes (for example, irritability and inability to concentrate)
Urticaria pigmentosa:
Tan or red-brown spots on the skin
Abdominal pain
Nausea
Vomiting
Diarrhea
Headache
Elevated heart rate
Facial flushing (reddening of the face)
Psychologic changes (for example, irritability and inability to concentrate)
Solitary mastocytoma:
Raised or flat reddish-brown spot on the skin
Hives
Itching
Diffuse erythrodermic mastocytosis:
Thickening of the skin
Blisters
Telangiectasia macularis eruptiva perstans:
Small lesions that do not itch
Systemic mastocytosis:
Skin lesions
Urticaria pigmentosa
Facial flushing
Itching
Nausea
Vomiting
Diarrhea
Abdominal pain
Ulcers in the stomach and duodenum (small intestine)
Headache
Lightheadedness
Heart palpitations
Bone pain
Anemia (low red blood cell count, which can cause fatigue)
Psychologic changes (for example, irritability and inability to concentrate)
Symptoms of systemic mastocytosis can sometimes occur as “attacks,” where multiple symptoms appear all at once. Following the attacks, the person may feel fatigued (tired) and lethargic (drowsy, lacking energy).
Doctors use many tests to diagnose disease and determine its extent. Some tests may also determine which treatments may be the most effective. A biopsy is the only way to make a definitive diagnosis of mastocytosis. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out more about the disease. Your doctor may consider these factors when choosing a diagnostic test:
Age and medical condition
The type of disease suspected
Severity of symptoms
Previous test results
In addition to a physical examination, the following tests may be used to diagnose mastocytosis:
Laboratory tests. Tests on samples of the patient’s blood and urine may be able to detect high levels of mast cells and histamine, respectively. Blood tests can also determine how the liver, kidneys, and other vital organs are functioning. Tryptase (an enzyme) may be elevated in the case of systemic mastocytosis, which may help differentiate systemic mastocytosis from similar disorders.
Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that mastocytosis is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). Skin biopsies are frequently used to diagnose mastocytosis.
Bone marrow aspiration and biopsy. A sampling of the bone marrow can be important in the diagnosis of systemic mastocytosis. The most common site to biopsy the bone marrow is the back of the pelvic (hip) bone. The skin is numbed and a needle is inserted into a bone in the hip until it reaches the marrow. A small amount of bone marrow is removed and examined under a microscope.
Staging is a way of describing a disease, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the disease’s stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery).
There is no standard staging system for mastocytosis.
The treatment of mastocytosis depends on the symptoms of the disease, its extent, and the person’s overall health. In many cases, a team of doctors will work with the patient to determine the best treatment plan.
There is no cure for mastocytosis, although several treatments can be used to relieve symptoms and remove mastocytoma (tumors). One important treatment for mastocytosis is to avoid anything that may cause a release of mast cell histamine, such as extreme temperatures, alcohol, emotional stress, insect bites, and certain medications.
This section outlines treatments that are the standard of care (the best treatments available) for this specific type of disease. Patients are also encouraged to consider clinical trials as a treatment option when making treatment plan decisions. A clinical trial is a research study to test a new treatment to prove it is safe, effective, and possibly better than standard treatment. Your doctor can help you review all treatment options. For more information, visit the clinical trials section.
Medications
Antihistamines can help relieve symptoms, such as itching, flushing, and other skin reactions. Other medications can help relieve diarrhea and stomach pain. Steroids may be used to reduce the size of skin lesions. Nonsteroidal anti-inflammatory drugs (NSAIDs) should be used with caution, as these medicines may trigger the release of histamine and can cause severe reactions. Often, people being treated for mastocytosis will carry a syringe of epinephrine (a hormone made by the adrenal glands) in case of emergency, such as a severe allergic reaction.
Ultraviolet light
Sometimes, the rashes may be exposed to a source of ultraviolet (UV) light to relieve symptoms.
Surgery
Surgery may be performed to remove lesions. Many surgeries on the skin can be performed quickly and easily.
Chemotherapy
Chemotherapy is sometimes used when mastocytosis has become cancerous.
Chemotherapy is the use of drugs to kill cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body. The side effects of chemotherapy depend on the individual and the dose used, but can include fatigue, risk of infection, nausea and vomiting, loss of appetite, and diarrhea. These side effects usually go away once treatment is finished.
The medications used to treat cancer are continually being evaluated. Talking with your doctor is often the best way to learn about the medications you've been prescribed, their purpose, and their potential side effects or interactions with other medications. Learn more about your prescriptions through Cancer.Net's Drug Information Resources , which provides links to searchable drug databases.
Stem cell transplantation is not used frequently in people with mastocytosis because treatment results are inconsistent and because there are significant risks to this treatment approach.
Doctors and scientists are always looking for better ways to treat patients with mastocytosis. A clinical trial is a way to test a new treatment in order to prove that it is safe, effective, and possibly better than a standard treatment. Patients who participate in clinical trials are among the first to receive new treatments before they are widely available. However, there is no guarantee that the new treatment will be safe, effective, or better than a standard treatment.
Patients decide to participate in clinical trials for many reasons. For some patients, a clinical trial is the best treatment option available. Because standard treatments are not perfect, patients are often willing to face the added uncertainty of a clinical trial in the hope of a better result. Other patients volunteer for clinical trials because they know that finding new drugs and other therapies is the only way to make progress in treating mastocytosis. Even if they do not benefit directly from the clinical trial, their participation may benefit future patients with mastocytosis.
To join a clinical trial, patients must complete a learning process known as informed consent. During informed consent, the doctor should list all of the patient’s options, so the person understands how the new treatment differs from the standard treatment. The doctor must also list all of the risks of the new treatment, which may or may not be different from the risks of standard treatment. Finally, the doctor must explain what will be required of each patient in order to participate in the clinical trial, including the number of doctor visits, tests, and the schedule of treatment. Learn more about clinical trials, including patient safety, phases of a clinical trial, deciding to participate in a clinical trial, questions to ask the research team, and links to find cancer clinical trials.
Mastocytosis and its treatment can cause a variety of side effects. However, doctors have made major strides in recent years in reducing pain, nausea and vomiting, and other physical side effects of treatments. Many treatments used today are less intensive but as effective as treatments used in the past. Doctors also have many ways to provide relief to patients when such side effects do occur.
Fear of treatment side effects is common after a diagnosis of mastocytosis, but it may be helpful to know that preventing and controlling side effects is a major focus of your health-care team. Before treatment begins, talk with your doctor about possible side effects of the specific treatments you will be receiving. The specific side effects that can occur depend on a variety of factors, including the type of mastocytosis, its location, the individual treatment plan (including the length and dosage of treatment), and the person’s overall health.
Ask your doctor which side effects are most likely to happen (and which are not), when side effects are likely to occur, and how they will be addressed by the health-care team if they do happen. Also, be sure to communicate with your doctor about side effects you experience during and after treatment. For more information on the most common side effects of this disorder and different treatments, along with ways to prevent or control them, visit Cancer.Net’s section on Managing Side Effects , based on ASCO’s curriculum.
In addition to physical side effects, there may be psychosocial (emotional and social) effects as well. Learn more about the importance of addressing these needs in Cancer.Net’s section on Caring for the Whole Patient
For more information on late effects or long-term side effects, please read the After Treatment section or talk with your doctor.
After treatment for mastocytosis ends, talk with your doctor about developing a follow-up care plan. This plan may include regular physical examinations and/or medical tests to monitor your recovery for the coming months and years. Follow up visits will include blood tests and possibly scans or other imaging studies. Normally, follow-up visits are most frequent in the first three years after treatment; patients are encouraged to have lifelong, follow-up care.
People who received ultraviolet (UV) rays for the treatment of cutaneous mastocytosis should be aware of increased risk of skin cancer in the future. Follow-up physical examinations and skin evaluations are important in the early diagnosis and prevention of this condition.
Several long-term side effects of chemotherapy may occur:
People who have received certain chemotherapy to the lungs may develop lung damage.
Heart damage in the form of a weakened heart muscle may occur in people who have received a higher dose of doxorubicin (Adriamycin) or radiation therapy to the chest.
Infertility (inability to have children) or premature menopause can occur in people who have received high-dose cyclophosphamide (Cytoxan, Neosar) or other chemotherapy.
Secondary leukemia and secondary cancers (cancers that develop as a result of the treatment for another type of cancer) are more common in people who were treated with chemotherapy.
People recovering from mastocytosis are encouraged to follow established guidelines for good health, such as maintaining a healthy weight, eating a balanced diet, and having recommended cancer screening tests. Talk with your doctor to develop a plan that is best for your needs. Moderate physical activity can help rebuild your strength and energy level. Your doctor can help you create an appropriate exercise plan based upon your needs, physical abilities, and fitness level. Learn more about Healthy Living After Cancer.
Research for mastocytosis is ongoing. The following advances may still be under investigation in clinical trials and may not be approved or available at this time. Always discuss all diagnostic and treatment options with your doctor.
Some cases of mastocytosis are associated with mutations of the c-kit tyrosine kinase receptor, which causes mast cell growth. Investigators are testing a drug called imatinib (Gleevec) in people with mastocytosis. Some people have shown good clinical results. Other new tyrosine kinase inhibitors such as dasatinib (Sprycel) and nilotinib (Tasigna) are also being investigated.
Regular communication with your doctor is important in making informed decisions about your health care. Consider asking the following questions of your doctor:
What type of mastocytosis do I have?
Can you explain my pathology report to me?
How can I avoid the onset of symptoms?
What are my treatment options?
What clinical trials are open to me?
What treatment, or combination of treatments, do you recommend? Why?
What is the goal of this treatment plan?
What are the possible short-term and long-term side effects of each treatment?
How will this treatment affect my daily life? Will I be able to work, exercise, and perform my usual activities?
How long will it take to heal?
What is the likelihood that mastocytosis will come back?
Are there other lesions that should be biopsied?
Are there medications that I should avoid?
What is my prognosis (chance of recovery)?
What follow-up tests will I need, and how often will I need them?
What support services are available to me? To my family?
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