Acute undifferentiated leukemia is a very rare type of aggressive leukemia — a type of cancer. It’s a very serious condition because researchers don’t know much about it.

Leukemia is a type of cancer of the white blood cells, which are also called leukocytes. It can also affect other parts of your body that are related to your blood, such as bone marrow.

Types of leukemia are divided up based on the type of white blood cells that are cancerous (their morphology). This could be the myeloid type or the lymphoid type of white blood cells.

Leukemia types can also be divided up according to how aggressive they are. Chronic leukemia is less aggressive, while acute leukemia is more aggressive.

Therefore, there are four subtypes of leukemia:

  • chronic lymphocytic leukemia
  • chronic myeloid leukemia
  • acute lymphocytic leukemia
  • acute myeloid leukemia

There are also many types of rare leukemias. Some of these fall into the category of acute leukemia of ambiguous lineage (ALAL). These are acute leukemias that don’t neatly fit into either the lymphocytic or the myeloid category.

Acute undifferentiated leukemia (AUL) is one type of ALAL. It’s very rare, so doctors don’t have a lot of information about the best ways to treat it. Therefore, AUL is quite serious.

Let’s go over the information we do have about AUL.

Medical experts do not know the exact causes of leukemia. This is true of AUL as well.

Some factors may increase your risk of developing any type of acute leukemia, including AUL. Risk factors can include:

Having one or several risk factors does not guarantee that you will get AUL. Likewise, you can develop AUL without having any of these risk factors. But the risk factors increase the likelihood that you might develop AUL or another acute leukemia.

AUL is a very rare disease, so the symptoms are not as well understood as those of more common conditions. If you have AUL, you might have one or many of the symptoms below, but you could also have symptoms that have not yet been identified.

Symptoms of AUL can include:

Many forms of leukemia can be classified by genetic markers and how the affected cells look under a microscope. AUL is defined by the fact that it does not fit into either the lymphocytic or the myeloid leukemia category.

However, as analysis methods have improved, doctors have found more ways to classify cases of leukemia as lymphocytic or myeloid. This has led to fewer AUL diagnoses overall.

If your doctor suspects that you have leukemia, they will likely want to take some blood samples for analysis. You might also need a bone marrow biopsy or an imaging test such as a CT scan. Once the results of the tests have been analyzed, your doctor may have enough information to diagnose AUL.

AUL can be difficult to treat because healthcare professionals do not know which types of markers to target. Treatments used for other types of leukemia might be helpful, but they could also be harmful.

Because AUL is so rare, doctors haven’t yet figured out the best way to treat it.

Some case studies and reviews describe positive results with chemotherapy and with allogeneic peripheral blood stem cell transplants, which use stem cells that come from another person’s blood. But more research is still needed.

Your doctor can help you weigh the risks and potential benefits of the treatment options for your situation.

In one review, researchers looked at AUL diagnoses in the United States between 2000 and 2016. In all, there were 1,888 cases of AUL.

The researchers looked at the overall survival rates of the group. This means they considered how long each person with AUL lived after their AUL diagnosis, regardless of their cause of death.

People with AUL who received chemotherapy had a median overall survival of 13 months, while those without chemotherapy had a median overall survival of 1 month. When researchers considered all people with AUL together, about 50% lived for at least 1 year, and the 5-year survival rate was less than 20%.

What is a 5-year survival rate?

Health professionals often use 5-year survival rate as a measure of a disease’s outlook. It describes the percentage of people with the disease who are still alive at least 5 years after their diagnosis.

Doctors may also use the 5-year relative survival rate, which is a measure of how many people with the disease are alive 5 years later compared with people without the disease.

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If you’ve received a diagnosis of AUL, you may feel a range of emotions, including anger, sadness, and fear. You may also want to learn more about the condition and find support for concerns such as transportation to medical appointments and how to manage bills.

Support groups such as the Leukemia & Lymphoma Society can be a good resource for connecting with others who currently have or previously had similar experiences.

You may also be interested in participating in a clinical trial. You can talk with your doctor about your treatment goals to learn more about your options.

You may still have some basic questions about AUL. Let’s take a look at some of the most common ones.

What is the difference between leukemia and acute leukemia?

“Leukemia” is a broad term for cancers of the bone marrow, in which the white blood cells are made. Acute leukemias have a high volume of immature cells. This means they are more aggressive and can make someone sick from cancer more quickly.

Can acute leukemia be cured completely?

With treatment, it is possible for acute leukemia to go into remission. This means there are no longer any detectable signs of cancer. If you’re in remission for a prolonged period, you could be considered cured, but your healthcare team may recommend continued close monitoring.

What is the prognosis of acute undifferentiated leukemia?

The outlook for acute undifferentiated leukemia will be different for every person. Because it’s so rare and doesn’t fit into the usual leukemia classifications, there’s no agreed-upon treatment plan.

Younger adults seem to have better outcomes than older adults, but more research is still needed. Experts generally consider the outlook to be poor, but your doctor can give you more information based on your unique circumstances.

Acute undifferentiated leukemia is a very rare type of blood cancer that doesn’t have any of the markers typically used to classify leukemias as lymphocytic or myeloid.

This can make AUL difficult to treat effectively, though some people with AUL do experience remission. If you have AUL, you might want to consider participating in a clinical trial and finding a support group.