Mast cell leukemia (MCL) is a quick-progressing condition that leads to the buildup of mast cells in your bone marrow and other tissues. It falls into a group of diseases collectively known as systemic mastocytosis.
MCL can cause a variety of symptoms including low blood pressure, rashes, and itchy skin. It tends to have a poor outlook due to its rarity and lack of research on the best way to treat it.
Keep reading to learn everything you need to know about MCL, including how it differs from other types of leukemia and the latest treatment options.
MCL is an extremely rare condition that falls into a group of diseases known as systemic mastocytosis. Mastocytosis is a group of conditions characterized by the abnormal growth and buildup of a type of white blood cell called mast cells in your bodily tissues.
What are mast cells?
Mast cells are a type of white blood cell produced by your bone marrow. One of their primary functions is to release histamines and other chemicals to help fight infections. These chemicals also produce many classic allergy symptoms like excess mucus, itchiness, and swelling.
Mastocytosis can be divided into two types:
- Cutaneous mastocytosis. This is when large numbers of mast cells gather in your skin but not in other parts of your body. It’s most common in children.
- Systemic mastocytosis. This happens when mast cells gather in tissues like your skin, organs, and bones. This is the category that MCL falls into.
All the blood cells in your body start off as hematopoietic stem cells, also known as blood stem cells. They’re found in your bone marrow. These stem cells become one of two types of cells:
- myeloid progenitor cells
- lymphoid progenitor cells
Leukemia is a group of cancers that’s caused by cells in your bone marrow that produce abnormal or underdeveloped blood cells. Leukemias are classified based on the type of cells that are affected.
MCL is one of several types of leukemia that are caused by the abnormal growth of cells from myeloid progenitor cells. Myeloid progenitor cells can become mast cells, platelets, red blood cells, and white blood cells.
In people with MCL, at least 20 percent of mast cells in your bone marrow or 10 percent of the mast cells in your blood are abnormal. The buildup of these cells can lead to
It’s not entirely clear why MCL develops, but several gene mutations in the KIT gene are linked to the development of MCL. In about
The following are symptoms among patients with mast cell leukemia may experience:
MCL most commonly occurs in adults. Half of people with MCL are over age 52, but some as young as 5 years old have been described in the medical literature.
A diagnosis for mast cell leukemia requires you to:
- meet the criteria for systemic mastocytosis
- show signs of organ damage
- have at least 20 percent atypical mast cells in your bone marrow or ten percent in your blood
For a systemic mastocytosis diagnosis, the
- clusters of at least 15 mast cells in bone marrow biopsies
- more than 25 percent of mast cells are atypical measure in bone marrow
- KIT gene mutation at codon 816 in bone marrow or other internal organs
- mast cells exhibit CD2 or CD25
- baseline serum tryptase level greater than 20ng/mL
To diagnose systemic mastocytosis and MCL, an oncologist will likely order a bone marrow biopsy. This is when a small tissue sample is taken with a long needle, often from your hip bone. The doctor may also take a biopsy of other affected organs.
Medical professionals can use your biopsy sample to look for certain genes that are common in people with MCL. They’ll run tests to assess the density and appearance of your mast cells.
A blood test may be ordered to search for markers of MCL like:
There’s no standard therapy for MCL due to the rarity of the disease and lack of research. Also, no one particular treatment has shown consistently effective results.
Allogeneic bone marrow transplants are also sometimes needed. This procedure involves transplanted bone marrow stem cells from a donor to replace cells damaged by chemotherapy.
Example treatment course
A 2017 study describes a man in his 50s with MCL who went into remission. Remission means the cancer could no longer be detected in his body after treatment.
The man initially received chemotherapy with the drugs:
- 0.1 mg/kg 2-Chloro-dexoy-adenosine every 24 hours for 7 days
- 20 mg dasatinib twice per day
The man showed some initial improvement but after 2 months, had worsening symptoms. The man then received another round of chemotherapy consisting of:
- 0.1 mg/kg 2-Chloro-dexoy-adenosine every 24 hours
- 0.8 mg/kg busulfan every 6 hours for 4 days
- 60 mg/kg cyclophosphamide for 2 days
After his second round of chemotherapy, the man received an allogeneic bone marrow transplant.
At the time the study was published, the man was in remission for 24 months. The man needed to take medication to control chronic graft versus host disease. This disease occurs when your body sees the transplanted cells as foreign invaders and attacks them.
Despite the promising results of the study, more research is needed to understand how to best treat MCL.
According to the authors of the study, there are fewer than 20 cases of MCL treated with an allogeneic bone marrow transplant reported in the literature. Most patients failed to go into remission.
The outlook for MCL is generally poor. About half of people who develop MCL live less than 6 months from the time of diagnosis. MCL often leads to multiorgan failure or anaphylactic shock due to the buildup of mast cells.
Despite the poor prognosis, some people have a better result. The man in the 2017 case study went into full remission after receiving treatment, and some people’s disease progresses slower than predicted.
The diagnosis and treatment process for leukemia can be overwhelming for anyone. However, it’s important to remember that you are not alone and new treatments are being studied.
As researchers continue to learn about MCL, treatment will likely become more refined in the future, and it’s possible the outlook of the disease will improve.
There are also many resources available that can offer support, including:
- Your cancer care team. Your doctors can recommend a mental health professional who specializes in the needs of those with cancer. There may also be a leukemia support group available at your treatment center.
- Leukemia and Lymphoma Society (LLS). The LLS offers a variety of support resources, including access to patient support groups, support for caregivers, and information on financial support programs.
- CancerCare. CancerCare has support resources for those impacted by cancer, including resources specific to people with leukemia. Check them out here.
The following organizations also offer tips and resources for managing the costs of cancer care:
- American Cancer Society
- American Society of Clinical Oncology
- Cancer Care
- Cancer Financial Assistance Coalition
- Leukemia & Lymphoma Society
- National Cancer Institute
Managing a MCL diagnosis can be challenging, but there are many resources that can help you cope with the physical, emotional, and financial challenges you may face.