Mast cell leukemia (MCL) is a very rare type of blood cell cancer. It causes the body to produce a large number of mast cells that can affect different areas of the body. MCL is an aggressive type of systemic mastocytosis, and the outlook for people with the condition is usually poor.

MCL is a subtype of mastocytosis. Mastocytosis is a condition that can involve excess mast cells in the skin, bone marrow, and internal organs, including the liver, spleen, gastrointestinal tract, and lymph nodes.

People with MCL have a circulating presence of mast cells in their bloodstream that is greater than 10%. They may also have immature mast cells in their bone marrow at a rate of over 20%. MCL is the rarest subtype of mastocytosis.

This article explains what MCL is and how it can affect the body. It also covers the outlook and treatment options for the condition.

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Cancer causes cells in the body to rapidly divide and reproduce. This can cause tumors to develop, damage the immune system, and cause other problems in the body.

Leukemia is a cancer of the blood or bone marrow. MCL is a rare and aggressive type of leukemia that causes a large number of mast cells to be present in the bone marrow and blood. Doctors also consider MCL to be an aggressive type of systemic mastocytosis, which is a condition that causes large numbers of mast cells to build up in the body.

Mast cells are immune cells in connective tissues throughout the body. These cells have a role in inflammatory responses, which include helping defend against parasites and allergens.

MCL is a very rare form of aggressive systemic mastocytosis. It accounts for under 1% of all cases of mastocytosis.

Because of its rarity, research into MCL is not yet extensive. However, some researchers are investigating new treatment options that could help treat this condition.

One example of this is stem cell transplant surgery. However, to date, there are only 20 reported cases of this procedure associated with this condition in medical literature.

MCL is extremely aggressive. The average survival time for a person with MCL is under 6 months.

It is important to remember that these figures are estimates and are based on the results of previous studies or treatments. A person can talk with a doctor about how their condition is likely to affect them.

MCL can cause organ and bone marrow failure, which can be life threatening. This happens because of the damage that excess mast cells in the blood cause to organs.

The bodies of people with MCL are also often resistant to certain leukemia treatments.

That said, one review describes a person who had MCL and remained in remission for 2 years as of 2017. The researchers write that this was due to a stem cell transplant, though they call for further studies to better investigate the effectiveness of this treatment for this condition.

MCL can occur on its own as a result of a genetic mutation. This is known as de novo. It may also occur as a result of systemic mastocytosis.

One 2017 study of 28 people with MCL found that 43% of the participants had MCL that had evolved from another type of systemic mastocytosis and that 57% of the participants developed MCL de novo.

People with MCL often display symptoms of mast cell activation syndrome. This occurs when the mast cells release the substances inside of them into the body at the wrong time.

Symptoms of this include:

Some other signs and symptoms of MCL include:

Some rarer symptoms include frequent urination and neuropsychiatric symptoms, such as delusions and hallucinations.

Doctors diagnose MCL by measuring the number of mast cells present in the blood and bone marrow.

To do this, they will take a bone marrow sample. They will often take this sample in two steps. First, they will remove liquid bone marrow in a process called aspiration. They will then remove a small amount of bone filled with marrow, or a biopsy. They will often take both of these samples during the same procedure.

Doctors will often take these samples from a person’s hip bone. They will begin by numbing the area with a local anesthetic. The person may also receive a mild sedative.

The doctor will then use a hollow needle to remove some liquid bone marrow before removing the small piece of bone filled with marrow. Some people may experience slight pain near the injection site for a few days after the procedure.

The doctor may also take a blood sample. They will then analyze the bone marrow and blood samples, looking for the presence of excess mast cells.

A diagnosis is possible when there are more than 20% of atypical mast cells in the bone marrow and 10% in the blood.

Learn more about bone marrow biopsies here.

There are very few treatment options available to people with MCL. This is because of how rare the condition is, meaning that very few clinical trials have studied it.

However, there are some treatment options available. These include treatments for systemic mastocytosis. Some treatment options for this condition include:

  • Rydapt: Also known by its generic name midostaurin, this medication may help treat systemic mastocytosis or MCL.
  • Corticosteroids: High doses of these drugs can reduce the mast cell burden on the body and reduce some of the symptoms, including flushing, pain, and cardiac failure. A person may undergo proton pump inhibitor therapy at the same time to combat the risk of gastrointestinal bleeding that corticosteroids can cause.
  • Chemotherapy: Chemotherapy may be an option, but there is little evidence to suggest that it can be an effective treatment for MCL. In one study, 6 out of 51 people with MCL received chemotherapy. However, the response rate was not available for all participants, the average survival time was 7 months, and every person in this group died between 2 and 29 months.
  • Bone marrow transplantation: Bone marrow transplantation may play a role in helping cure MCL. Some reports have shown a positive role that transplantation can play in managing MCL, but doctors believe it has limited ability to eradicate the condition completely.
  • Targeted therapies or tyrosine kinase inhibitors: Examples of these drugs include imatinib, masitinib, and dasatinib. Doctors use these drugs to treat systemic mastocytosis, but more research is needed to see if they can be effective treatments for MCL.
  • Stem cell transplant: One 2017 study describes a person with MCL who had been in remission for 2 years at the time of writing. Doctors had performed a stem cell transplant for this person. Stem cell transplants are another treatment option for systemic mastocytosis, but research into these procedures for MCL is not extensive.

People with MCL should discuss the benefits and risks of potentially aggressive treatment options with a doctor. The doctor may also recommend palliative care treatment to improve the person’s quality of life.

Learn more about palliative care here.

MCL is a very rare type of systemic mastocytosis and a rare form of blood cancer.

The condition causes the body to produce excess numbers of mast cells. These cells live in connective tissues in the body and play a role in the body’s inflammatory response to infections and allergens.

MCL is an aggressive form of cancer, and the outlook for people with the condition is not good. The average survival time for a person with MCL is 6 months.

There has been very little research into potential treatment options for MCL. Some possible treatments may include treatment options for systemic mastocytosis, such as corticosteroids, chemotherapy, and bone marrow transplants. However, more research is needed to determine whether or not these treatments are effective for MCL.