Mast Cell Leukemia: Causes, Signs and Symptoms, Diagnosis and Treatment

Introduction:

Mast cell leukemia (MCL) is a very rare form of blood cancer. It usually grows quickly and can lead to severe symptoms. This can affect people of all ages but is very rare. In this condition, there is a building-up of mast cells (a type of immune cell) in the bone marrow and other tissues. Mast cell leukemia (MCL) comes under a group of diseases collectively known as systemic mastocytosis, and mast cell leukemia is the rarest form of systemic mastocytosis, occurring in less than one percent of people.

What Is Mast Cell Leukemia?

Mast cell leukemia (MCL) is an extremely rare blood cancer that falls in the group of diseases called mastocytosis. Mastocytosis means the abnormal growth and buildup of mast cells, a type of white blood cell in various locations in the body, such as body tissues and bone marrow. The symptoms that are seen in mast cell leukemia are the same as in mastocytosis and may include symptoms like low blood pressure, rashes, and itchy skin.

What Are Mast Cells?

Mast cells are part of the body’s immune system. These cells are produced in the bone marrow (spongy tissue present inside certain bones) and are also seen in different organs throughout the body. These cells play an important role in protecting the body from various infections and are also responsible for allergic reactions in the body. These cells usually present abundantly in the areas where the body meets the environment, such as the skin, lungs, and intestinal tract. Mast cells are also responsible for other essential functions of the body, such as wound healing, bone growth, and forming new blood vessels.

What Is Mastocytosis?

Mastocytosis is a condition leading to the abnormal accumulation of mast cells under the skin or in the bones, intestines, and other organs. There are different forms of mastocytosis caused by high levels of mast cells in the body, and two of the most common ones include systemic mastocytosis and cutaneous mastocytosis. Cutaneous mastocytosis usually affects the skin, and systemic mastocytosis affects the whole body. According to the World Health Organization, mast cell leukemia is considered a type of aggressive or fast-growing systemic mastocytosis.

Systemic Mastocytosis -

In systemic mastocytosis, the mast cells are seen in different organs and can lead to allergic reactions or inflammation when the body gets exposed to certain allergens, such as alcohol or spicy foods. The symptoms experienced by the patient may be mild or severe and can lead to organ damage. Mast cell leukemia can develop in the mild form of systemic mastocytosis but is seen in very few cases, about seven percent in children and 30 percent in adults. Moreover, it has been found that less than one percent of all mastocytosis cases are mast cell leukemia.

What Are the Causes of Mast Cell Leukemia?

• The majority of the blood cells in the body start as hematopoietic stem cells, known as blood stem cells. These are present in the bone marrow. In the later stage, these cells get converted into one of these cells: myeloid progenitor cells or lymphoid progenitor cells.

• Mast cell leukemia is one of several types of leukemia (a type of blood cancer caused by cells present in the bone marrow), which is caused by the abnormal growth of cells from myeloid progenitor cells. The myeloid progenitor cells can develop into any of the following cells such as mast cells, platelets, red blood cells, and white blood cells.

• People affected with mast cell leukemia have at least 20 percent of abnormal cells in the bone marrow or 10 percent of abnormal mast cells in the blood. The abnormal building up of these cells can lead to organ dysfunction in certain organs like the spleen, liver, or bone marrow.

• However, it is not entirely clear how mast cell leukemia occurs, and in some cases, it is also linked to genetic mutations in the gene called KIT.

What Are the Signs and Symptoms of Mast Cell Leukemia?

People affected with mast cell leukemia can develop mast cell activation syndrome (MCAS). In this condition, the mast cells cause an allergic reaction without the presence of any allergen in the body. This can lead to certain signs and symptoms, which include -

• Fever.

• Flushing (warmth and reddening of the skin).

• Diarrhea.

• Fast heart rate.

• Malaise (generally feeling unwell).

Apart from these, some of the following signs and symptoms can also occur, which include -

• Weakness.

• Loss of appetite.

• Weight loss.

• Splenomegaly (enlarged spleen).

• Hepatomegaly (enlarged liver).

• Lymphadenopathy (swollen lymph nodes).

• Stomach or intestine ulcers lead to pain, nausea, or bloating.

• Blood in vomit or stool due to bleeding in the gastrointestinal (digestive) system.

• Anemia (low level of red blood cells).

• Thrombocytopenia (low platelet counts).

In severe cases of mast cell leukemia, organ damage can also occur due to the accumulation of mast cells, which can cause serious complications.

What Is the Diagnosis of Mast Cell Leukemia?

The diagnosis of mast cell leukemia can be done by performing various tests, which may include -

• Bone Marrow Test - This is considered an important test in the diagnosis of MCL. In this, a sample of cells from the bone marrow is taken with a procedure called bone marrow biopsy or bone marrow aspiration to check the level of mast cells. Diagnosis is confirmed if 20 percent of the bone marrow cells are mast cells.

• Blood Test - A sample of the patient's blood may be used to examine the serum levels of an enzyme called tryptase. High levels of this enzyme mean the person is affected with systemic mastocytosis, which is caused by high levels of mast cells.

• Genetic Testing - Genetic mutation is considered one of the other factors leading to the development of mast cell leukemia. Therefore, with the help of genetic sequencing, the type of mutation may be determined. The type of mutation in the mast cells may help the physician determine if someone has systemic mastocytosis or not.

• Flow Cytometry - This test measures the type of proteins found on the surface of the cell. In people with systemic mastocytosis, the mast cells that carry specific proteins on their surface can be determined with the help of this test.

What Is the Treatment for Mast Cell Leukemia?

Mast cell leukemia is a very rare condition, and therefore, the treatment for this is also limited. Still, there are some treatment options available for this condition which may include -

• Steroid Therapy - A high dose of corticosteroids may help in reducing the abnormal number of mats cells in the body and also helps in reducing the symptoms.

• Bone Marrow Transplantation - This can be done in serious cases in which the healthy bone marrow is transplanted into the patient’s body. However, this option is still under investigation as it has limited ability to cure the condition.

• Chemotherapy - This is another option available to treat mast cell leukemia, but this is still controversial due to its effectiveness in the treatment of MCL.

• Stem Cell Transplant - This option is available for younger patients who do not have any other health problems. In this procedure, new and healthy stem cells are transplanted in the place of damaged ones. During this procedure, the patient receives high-dose chemotherapy or radiation therapy to terminate old blood cells and stem cells. Only after that they can receive new stem cells from a donor.

• Targeted Therapies - Certain drugs like Imatinib, Masitinib, and Dasatinib can be given to target certain cells, such as mast cells, in this case, to treat the condition.

• Drugs - Midostaurin is considered one of the effective medicines in the treatment of systemic mastocytosis or MCL.

Conclusion:

Mast cell leukemia (MCL) is a very rare type of blood cancer. This can grow very quickly and may cause severe symptoms in the body. The treatment options for this condition are very limited, and it is still unknown whether they will work or not. Therefore, the prognosis of this condition is very poor, and the researchers are still going on to find a potentially effective treatment plan for this condition. Therefore, the patient should discuss the benefits and side effects of any treatment option with the doctor.