Leukemia and many other blood disorders can cause your spleen to enlarge.

Doctors divide leukemia into four primary categories:

All types of leukemia can lead to an enlarged spleen, but it generally occurs more frequently in chronic leukemias. Chronic leukemias develop slowly compared with acute leukemias which grow fast.

In this article, we explore what causes spleen enlargement in leukemia, its symptoms, and how it’s treated.

What does your spleen do?

Your spleen is an organ located on the left side of your abdomen next to your stomach and behind your ribs. Its main functions are:

  • filtering blood to remove old red blood cells
  • storing a blood reserve
  • helping your body fight infections
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In people with leukemia, cancerous blood cells can enter the spleen and other organs through the bloodstream or the lymphatic system. These abnormal blood cells replicate out of control and can cause the spleen to swell.

An enlarged spleen can occur in people with any type of leukemia, but it tends to be a more prominent feature of chronic leukemias.

Chronic myeloid leukemia (CML)

An enlarged spleen is the most common finding during an initial physical exam in people with CML. It’s seen in more than half of people. Massive enlargement is a prominent feature.

Spleen enlargement may be the only symptom at the time of diagnosis.

Chronic lymphocytic leukemia (CLL)

An enlarged spleen can be a prominent feature in people with CLL, but enlargement usually isn’t as large as with CML. It’s a common early symptom of a subtype called hairy cell leukemia.

The spleen, liver, and lymph nodes may rapidly swell in the late stages of the disease.

Childhood leukemias

In childhood leukemias, the most common forms of leukemia associated with an enlarged spleen at diagnosis are:

  • acute leukemias
  • CML
  • juvenile myelomonocytic leukemia

Can leukemia cause other organs to become enlarged?

Leukemia cells also build up in your liver and cause it to swell. Swollen lymph nodes are also common in people with leukemia. The T-cell subtype of ALL often causes swelling of the thymus, a small organ behind your breastbone.

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Other blood disorders that cause an enlarged spleen

A variety of other blood diseases can cause spleen enlargement. They include:

An enlarged spleen might not cause any symptoms. It occurs in about half of people with CML, but about 40% to 50% of people have no symptoms at diagnosis.

When symptoms are present, an enlarged spleen may cause:

  • pain in the upper left side of your abdomen
  • swelling in your belly
  • fullness after eating a small amount

You or your doctor may be able to feel your enlarged spleen through your skin. Usually, you can’t feel your spleen because your lower ribs cover it.

It’s important to visit your doctor if you experience symptoms that could indicate an enlarged spleen. An enlarged spleen can be the first sign of leukemia or another condition that requires prompt medical attention.

It’s important to seek emergency attention if you have severe pain or if the pain gets worse when you breathe.

Treatment for an enlarged spleen starts by targeting underlying leukemia. Treatment often includes some combination of:

If an enlarged spleen is causing symptoms, your doctor may recommend additional treatments.

They may recommend a low dose of radiation to target leukemia cells in your spleen and ease symptoms like difficulty eating and pain.

In rare cases, a splenectomy may be needed

A splenectomy, or spleen removal surgery, may be performed in rare cases to reduce symptoms. Removing the spleen may improve your blood cell counts and reduce your need for blood transfusions, but it also comes with risks, such as an increased chance of:

Among 5,333 people treated for CLL at the Mayo Clinic from 1995 to 2015, only about 2% of people had their spleen removed.

If your spleen is enlarged, your doctor will likely advise you to avoid activities with a risk of abdominal injury since you may be at an increased risk of rupture. A ruptured spleen can be life threatening.

Can people live without a spleen?

You can live a typical life without a spleen, but you will be at an elevated risk of some types of infection. Your doctor will likely recommend vaccination against bacteria such as:

  • Haemophilus influenzae
  • Streptococcus pneumoniae
  • Neisseria meningitidis

Is there any way to prevent an enlarged spleen from occurring?

An enlarged spleen is common in people with some types of leukemia. You may be able to lower your risk of an enlarged spleen by lowering your risk of developing leukemia. Potential ways to lower your risk include:

  • avoiding smoking
  • maintaining a healthy weight
  • avoiding breathing in the chemicals benzene and formaldehyde

Can your spleen rupture from being enlarged?

An enlarged spleen is at a higher risk of rupture. A rupture can be life threatening. A rupture is usually caused by a direct blow to the left side of your chest.

How big is an enlarged spleen?

An enlarged spleen is measured by weight or size. The size and weight of a spleen vary according to height, weight, and sex. Larger spleens are typically found in males and heavier or taller people.

An adult spleen typically weighs 70 to 200 grams (2.4 to 7 ounces) and measures up to 12 centimeters in length (4.7 inches). An enlarged spleen weighs between 400 to 500 g (14 to 17.6 oz.) and measures 12 to 20 cm (4.7 to 7.9 in.).

What other conditions cause an enlarged spleen?

Many conditions besides leukemia can cause an enlarged spleen. They include:

An enlarged spleen can be a symptom of leukemia. A massively enlarged spleen is particularly common among people with CML. Enlargement is also common in CLL, but it tends to be smaller.

Your doctor can advise you about whether your enlarged spleen needs particular treatment. If it’s causing problems or at a high risk of rupturing, your doctor may recommend radiation therapy or having it removed.