Primary myelofibrosis (PMF) is a rare bone marrow disorder that affects the production of blood cells. It causes scarring, or fibrosis, in the bone marrow, which reduces the body’s ability to produce healthy cells.

Primary myelofibrosis (PMF) belongs to a group of diseases in which the bone marrow produces too many atypical blood cells. While the exact cause is unknown, genetic changes play a central role in PMF development.

As a progressive disease, it can lead to severe complications, including anemia, an enlarged spleen, and a higher risk of developing acute leukemia.

This article discusses the symptoms of primary myelofibrosis, its causes, diagnosis, and treatment options. It also answers some frequently asked questions.

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Primary myelofibrosis (PMF) is a bone marrow disorder that belongs to a group of conditions called myeloproliferative neoplasms (MPNs), where the body produces too many blood cells.

Usually, bone marrow efficiently produces blood cells. In PMF, a DNA change leads to atypical blood stem cell growth, causing scar tissue to form in the bone marrow.

This scarring interferes with the bone marrow’s ability to produce healthy red blood cells, white blood cells, and platelets, reducing the number of functional blood cells overall. This can lead to serious complications such as severe anemia, bleeding and infections.

PMF is rare, affecting fewer than 50,000 people in the United States. Other names for PMF include:

  • agnogenic myeloid metaplasia
  • chronic idiopathic myelofibrosis
  • idiopathic myelofibrosis
  • myelofibrosis with myeloid metaplasia

Since MPNs involve uncontrolled cell growth of the bone marrow, doctors consider them types of blood cancer. While MPNs can raise the risk of leukemia, they do not guarantee a person will get it.

Primary myelofibrosis usually develops slowly. Some individuals may not have any symptoms in the early stages and may find out about it when having a blood test for something else.

However, as the disease progresses, the symptoms may include:

Approximately 10% to 20%Trusted Source of PMF cases progress to acute myeloid leukemia (AML) over a 10-year period, so early intervention is important.

PMF may also lead to complications such as:

If an individual experiences any of the above symptoms, it is important to contact a healthcare professional promptly.

The exact cause of PMF is unknown, but about 50% of cases involve a change in the JAK2 gene, while others may have changes in the MPL or CALR genes.

Doctors do not yet know how these genes contribute to PMF or why some people develop these changes while others do not.

However, doctors do not consider PMF to be hereditary. This is because these genetic changes are generally not present in the sperm or egg of the parents. Instead, the genetic changes are present in certain cells in the person’s body.

PMF can also develop due to the spread of cancer to the bone marrow from other cancerous tumors, or as a result of other bone marrow disorders, such as polycythemia vera or chronic myeloid leukemia.

A 2021 study noted that there may be a link between exposure to certain toxins and another type of MPN, known as polycythemia vera. However, whether this could apply to PMF is unknown.

Diagnosing PMF involves a combination of tests, which may include:

  • Blood tests: A complete blood count (CBC) may reveal anemia, a low platelet count, or elevated white blood cells.
  • Bone marrow biopsy: A bone marrow biopsy is essential for diagnosing PMF. A doctor examines a sample under a microscope to detect scarring, atypical cells, or an overproduction of certain blood cells.
  • Genetic testing: Testing for mutations in the JAK2, MPL, or CALR genes can help confirm the diagnosis and guide treatment decisions.
  • Imaging: A doctor may carry out imaging studies such as an ultrasound or a CT scan to assess the size of the spleen or liver.

Doctors also assign cases of PMF a grade, which describes how much fibrosis there is in the bone marrow.

PMF treatment may relieve symptoms, improve quality of life, and slow disease progression.

For some people, there may be the possibility of a stem cell transplant. This can sometimes lead to long-term remission, but it has significant risks and is not suitable for everyone.

The treatments a doctor recommends will depend on the severity of the condition, the patient’s age, and overall health.

The options include:

  • Medications: Doctors often prescribe JAK inhibitors such as ruxolitinib (Jakafi) to people with PMF. Other medications, such as hydroxyurea, pacritinib, or momelotinib, may also be options.
  • Blood transfusions: For patients with severe anemia, blood transfusions may be necessary to maintain adequate red blood cell levels.
  • Stem cell transplantation: Allogeneic stem cell transplantation offers a potential cure for younger patients with no other preexisting health problems. This procedure involves replacing the patient’s bone marrow with healthy stem cells from a donor.
  • Supportive care: This may include pain management, nutritional support, and monitoring for complications such as infections or bleeding.
  • Surgery: In rare cases, a doctor may recommend surgical removal of the spleen (splenectomy) if the spleen is severely enlarged and causing discomfort or other complications.

In this section, we answer some frequently asked questions about primary myelofibrosis.

What is the life expectancy for someone with myelofibrosis?

The life expectancy for individuals with PMF varies significantly based on factors such as disease stage and overall health.

In a 2022 retrospective studyTrusted Source of people with grade 2 PMF, the median overall survival time for those who received the JAK inhibitor ruxolitinib was 84 months. For all participants, the median survival time from 2011 to 2020 was 64 months, which was an improvement on the previous decade.

These figures are only averages, and they do not include people with earlier or more advanced PMF.

Can you recover from myelofibrosis?

There is no cure for myelofibrosis, but some patients can enter long-term remission through allogeneic stem cell transplants. However, this procedure carries significant risks, particularly for older or less healthy patients.

Reduced-intensity transplants, which use lower doses of chemotherapy and radiation, offer a potential option for higher risk individuals. People may wish to speak with a doctor about whether this is viable for them.

Primary myelofibrosis (PMF) is a rare disorder that leads to scarring in the bone marrow, disrupting the body’s ability to produce healthy blood cells.

Potential symptoms of PMF include fatigue, anemia, and an enlarged spleen. However, in the early stages, people can have no symptoms.

Although the exact cause of PMF remains unknown, genetics sometimes play a role in its development. Treatment focuses on managing symptoms and improving quality of life through medications, blood transfusions, and, in some cases, stem cell transplantation.

While the condition does not have a cure, ongoing advancements in treatment options offer hope for patients facing this challenging disease. Early detection and management can help control symptoms and improve quality of life.