Panmyelosis is usually referred to as acute panmyelosis with myelofibrosis (APMF) or acute myelofibrosis.

Myelofibrosis means there is scar tissue inside the bone marrow instead of normal tissue. This causes panmyelosis, which means that the bone marrow can't produce enough red blood cells, white blood cells or platelets.

APMF is a very rare form of acute myeloid leukaemia (AML). It's a disease that is difficult to diagnose and often develops very quickly.

Blood cells and leukaemia

To understand how and why leukaemia affects you as it does, it helps to know how you make blood cells.

Your body makes blood cells in the bone marrow. The bone marrow is the soft inner part of your bones. You make blood cells in a controlled way, as your body needs them.

All blood cells start as the same type of cell, called a stem cell. This stem cell then develops into:

  • myeloid stem cells become white blood cells called monocytes and neutrophils (granulocyte), red blood cells and platelets
  • lymphoid stem cells, which become white blood cells called lymphocytes

The diagram below helps to explain this.

A simplified diagram showing how blood cells are made

In acute myeloid leukaemia, the bone marrow makes too many monocytes or granulocytes. These cells are not fully developed and are not able to work normally.

Diagram showing the cells in which AML starts

In other types of leukaemia, usually only one type of myeloid cell becomes cancerous. But in APMF more than one type of myeloid cell is abnormal. Usually, cells called megakaryocytes are also abnormal in APMF.

Megakaryocytes are the cells that go on to become platelets. So it is sometimes confused with a type of leukaemia called acute megakaryoblastic leukaemia.


In APMF, the levels of red blood cells, white blood cells, and platelets are low. This is called pancytopenia. This can cause:

  • infections
  • tiredness
  • bleeding

You are usually referred quickly to a specialist in blood disorders (a haematologist), if you have these symptoms. Your specialist will try to take a sample (biopsy) of the bone marrow. They look at the cells under a microscope to check for leukaemia cells. 


APMF is very rare and there is no standard treatment. Most specialists are likely to treat it in the same way as other types of acute myeloid leukaemia (AML). Often symptoms become worse very quickly. 

You may have chemotherapy and you might have a transplant. Your healthcare team will consider the benefits of treatment and the possible side effects. For example, the treatment can temporarily reduce someone’s ability to fight infection, even more than the leukaemia does. Your team will explain things to you in more detail and monitor you carefully during treatment.


Coping with a diagnosis of a rare cancer can be especially difficult. Being well informed about your cancer and its treatment can help. It can make it easier to make decisions and cope with what happens.

Talking to other people who have the same thing can also help.

Our discussion forum Cancer Chat is a place for anyone affected by cancer. You can share experiences, stories and information with other people.

You can call our nurse freephone helpline on 0808 800 4040. They are available from Monday to Friday, 9am to 5pm. Or you can send them a question online.

The Rare Cancer Alliance offer support and information to people with rare cancers.

Last reviewed: 
29 Apr 2020
Next review due: 
28 Apr 2023
  • Differential diagnosis of myelofibrosis based on WHO 2008 criteria: acute panmyelosis with myelofibrosis, acute megakaryoblastic leukemia with myelofibrosis, primary myelofibrosis and myelodysplastic syndrome with myelofibrosis

    E Bae and others 

    International Journal of Laboratory Haematology, 2013. Volume 35, issue 6, pages 629 to 36

  • Acute Myeloid Leukemia Not Otherwise Categorized
    World Health Organization Classification of Tumors, Tumors of Haematopoietic and Lymphoid Tissues
    IARC Press: France, 2001

  • Acute Panmyelosis with Myelofibrosis: An Entity Distinct from Acute Megakaryoblastic Leukemia

    A Oraz and others

    Modern Pathology, 2005. Volume 18

  • Acute Panmyelosis with Myelofibrosis - A Rare Subtype of Acute Myeloid Leukemia

    T Chatterjee and others

    Mediterranean Journal of Hematology and Infectious Diseases, 2013. Volume 5, Issue 1

  • Hematology: Diagnosis and Treatment

    R Hoffman and others

    Churchill Livingstone, 2013

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