- Advanced systemic mastocytosis is a progressive condition characterized by the accumulation of mast cells in the body’s organs.
- There’s no cure for advanced systemic mastocytosis, but many of the symptoms can be treated.
- For people with aggressive forms of the disorder, cladribine, midostaurin, and bone marrow transplants can help slow its progression.
Systemic mastocytosis is a rare disorder characterized by the buildup of mast cells, a type of immune cell, in various organs throughout the body.
Mast cells are involved in fighting off foreign invaders like germs and viruses. They produce a chemical called histamine that recruits other immune cells and sets off an inflammatory response.
Mastocytosis is caused by mutations in a receptor on the mast cells’ surface. This receptor helps regulate cell growth and division.
These mutations turn the receptor into a chronic “on” state, resulting in mast cells being produced at greater levels than needed for the immune system.
As a result, these cells can build up in the skin and internal organs, according to the Genetic and Rare Diseases Information Center. This may include the:
- bone marrow
- small intestines
- lymph nodes
In advanced systemic mastocytosis, mast cells build up progressively within the organs, which causes tissue damage and interrupts usual organ function. This can lead to organ failure.
One of the first symptoms usually associated with systemic mastocytosis is a spotty rash caused by the buildup of mast cells under the skin.
According to the American Academy of Allergy Asthma & Immunology, as the disease progresses and other organs become affected, people may experience:
- gastrointestinal pain or distress, including nausea, vomiting, or diarrhea
- muscle and bone pain
Because mast cells regulate the immune response, symptoms of an allergic response can also occur, including flushing and shortness of breath.
In severe cases, low blood pressure can cause fainting. Some people may even experience a severe allergic reaction known as anaphylaxis.
Your doctor will diagnose your systemic mastocytosis as advanced if it satisfies certain criteria, per The Mast Cell Disease Society.
They may perform a bone marrow puncture and imaging to see if mast cell overproduction has gotten into the bone marrow or an organ other than the skin. These are major criteria for the condition.
Bloodwork may be performed to test for minor criteria such as:
- elevated levels of tryptase, a chemical released by mast calls
- cell surface markers
- the presence of a KIT mutation in mast cells
- high numbers of eosinophils, a type of white blood cell
There is no cure for advanced systemic mastocytosis, but many of the symptoms can be treated.
Treatments may include:
- Antihistamines: to manage the effects of histamine overproduction on the skin and gastrointestinal tract
- Bisphosphonates: to prevent bone loss
- Steroids: to reduce inflammation in the skin and gut and prevent intestinal malabsorption
- Epinephrine: to treat anaphylactic reactions
Cladribine, a kind of chemotherapeutic that targets immune cells, is also often used for people with advanced systemic mastocytosis.
Cladribine works by blocking replication of DNA in immune cells such as mast cells, preventing them from growing and spreading.
But cladribine can cause immunosuppression, according to 2015 research. This increases the likelihood of potential deadly infections. That’s why it’s often reserved for people with aggressive forms of the condition.
For some people with advanced systemic mastocytosis, midostaurin can help as well. Midostaurin was
Midostaurin works to block the activity of the mast cell receptor, according to a
In a 2016 clinical study, 60 percent of people with advanced systemic mastocytosis who received midostaurin experienced improvement in their symptoms. And 45 percent showed significant improvement.
According to the results of a
Imatinib, a kinase inhibitor, has been shown to be effective for people with forms of advanced systemic mastocytosis involving KIT mutations, according to
A bone marrow transplant may also help slow the progression of disease. Mast cells are made in the bone marrow, so replacing the stem cells that produce them can help slow their accumulation throughout the body.
According to the results of a
The life expectancy associated with systemic mastocytosis depends on the severity of the disease.
Indolent systemic mastocytosis progresses very slowly. In fact, a long-term study published in 2009 found that most people with indolent systemic mastocytosis had a standard life expectancy.
However, with more advanced disease, the outlook changes. According to the National Organization for Rare Disorders, advanced systemic mastocytosis can take the form of:
- blood disorders
- organ impairment or failure, usually affecting the:
- bone marrow
- mast cell leukemia
- a single tumor
In a 2009 study of 342 adults with systemic mastocytosis, those with aggressive disease had a median survival of about 3.5 years.
Keep in mind that these numbers are estimates, and that everyone’s situation is different. You and your care team can work together to find the best treatment for your individual condition.
Plus, more advanced treatment options available today may help people with advanced mastocytosis have an improved quality of life for a longer period of time.
In very rare cases, systemic mastocytosis can lead to mast cell leukemia. This condition is characterized by the rapid buildup of mast cells within the blood and bone marrow.
According to the American Society of Hematology, however, less than 1 percent of cases of mastocytosis progress to mast cell leukemia.
Mast cell leukemia is an aggressive form of cancer with a life expectancy of fewer than 6 months on average. However, disease treatment can help slow the progression of mast cell leukemia.
In the midostaurin study, people with mast cell leukemia lived a median 9.4 months with treatment. In a 2014 study, bone marrow transplants significantly improved the outlook, with approximately
Emerging treatments may improve the outlook even further.
Advanced systemic mastocytosis is a progressive disorder characterized by the accumulation of mast cells within the internal organs of the body.
As these cells build up, it can cause impaired organ function, leading to organ failure.
Though there’s no cure for systemic mastocytosis, treatment can help manage the symptoms.
For people with aggressive forms of the disease, cladribine, midostaurin, and bone marrow transplants can all help slow the progression of the disease.