Panmyelosis is usually referred to as acute panmyelosis with myelofibrosis (APMF) or acute myelofibrosis. This is a complex name, so breaking it down may help you understand what it means. 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 accounts for less than 2 out of 100 cases (2%) of acute myeloid leukaemia. It is a disease that is difficult to diagnose and often develops very quickly.
Leukaemia means a cancer of the blood forming system. The blood forming system is found in the bone marrow, which is the soft inner part of your bones. Most types of leukaemia cause abnormal white blood cells (blasts) to be made in the bone marrow. White blood cells normally fight infection and are part of our immune system. These abnormal cells can get into the blood stream and circulate around the body. Because they don’t work normally, these cells are not able to protect you from infection as they should.
In leukaemia there are far too many of these abnormal white blood cells, which stop the other blood cells from developing normally. This can lead to a condition called anaemia. Anaemia means that you have too few red blood cells circulating through your body. Bleeding and bruising can also happen due to a lack of platelet production. Platelets help the blood to clot. There is more information on blood cells and leukaemia in the about acute myeloid leukaemia section.
Leukaemia is called acute or chronic depending on how fast it develops. Acute leukaemia can get worse very quickly if it isn’t treated.
There are many types of leukaemia. The name given to the type of leukaemia you have depends on the type of white blood cells that are affected. The bone marrow makes the blood cells, which then develop along different pathways and turn into several different types of specialised cells. Different leukaemias have faults at different places in the growth process of the blood forming cells.
Many years ago doctors thought that there were only two types of acute leukaemia. These were acute lymphoblastic leukaemia (ALL) which affects the lymphoid blood cells, and acute myeloid leukaemia (AML) which affects the myeloid cells. We now know that there are different sub types of AML depending upon exactly which type of myeloid cell has become leukaemic and at what stage of its development.
Myeloid cells include:
- Neutrophils which mainly fight bacterial infection
- Monocytes which destroy more resistant bacteria
- Eosinophils which are important in defence against parasites and which are involved in allergic reactions
- Basophils which are also involved in allergic reactions
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.
Often in APMF, the levels of all the blood cells are low. Doctors call this pancytopenia. This can cause the symptoms of infections, tiredness and bleeding that are common in acute leukaemia. People with these symptoms are usually referred quickly to a specialist in blood disorders (a haematologist). The specialist will do a bone marrow test. This test can diagnose the type of leukaemia that someone has.
As APMF is rare, there is very little published information about this disease and its treatment. But most doctors are likely to treat it in a similar way to other types of AML.
Sadly, APMF is a quickly developing illness and people with it can often become ill very quickly. Chemotherapy may not always work and can have severe side effects. Some of these side effects can be life threatening in themselves. For example, the treatment can temporarily reduce someone’s ability to fight infection even more than the leukaemia does. So it is possible that patients can die from infections during or soon after their treatment.
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