Tests for Castleman Disease

People with Castleman disease (CD) may see their doctor because of symptoms they are having, or because they just don’t feel well and go in for a checkup. Sometimes CD is found in people without symptoms when it’s found on an imaging or blood test being done for another reason.

CD is rare, and its symptoms are often like those caused by other diseases (including infections, autoimmune diseases, and lymphomas), so doctors often suspect it is something else at first. The diagnosis of CD does involve looking at any symptoms the patient may have and blood test results. However, an actual diagnosis is made when doctors remove an affected lymph node and look at it with a microscope. This procedure, known as a biopsy, is described below.

Medical history and physical exam

If your symptoms or the results of a test suggest you might have a lymph node problem such as CD, your doctor will want to get a thorough medical history, including the details of any symptoms, possible risk factors, family history, and other medical conditions.

Next, the doctor will examine you, paying special attention to lymph nodes and other areas of your body that could be involved, including the spleen and liver. Because infections are the most common cause of enlarged lymph nodes, the doctor will look for an infection in the part of the body near the swollen lymph nodes.

If the doctor suspects that CD or another serious problem (such as lymphoma) might be causing the symptoms, he or she will probably order blood tests, imaging tests, and/or do a biopsy of an affected lymph node (see below).

Blood tests

Blood tests are likely to be done if the doctor suspects CD, some other type of immune system problem, a serious infection, or other conditions. Some of the types of blood tests that can be abnormal in people with CD include:

  • Complete blood count (CBC)
  • Interleukin-6 (IL-6)
  • Erythrocyte sedimentation rate (ESR)
  • C-reactive protein (CRP)
  • Kidney function tests

Having abnormal results for these lab tests doesn’t prove someone has CD, because other conditions can also cause these problems. But these and other blood tests can help doctors make the right diagnosis.

Imaging tests

Imaging tests use x-rays, magnetic fields, sound waves, or radioactive particles to create pictures of the inside of the body. These tests may be done for a number of reasons, including

  • To look for enlarged lymph nodes or organs that might be causing symptoms
  • To look for enlarged nodes in other parts of the body
  • To help determine if treatment is working

People who might have CD (or another lymph node problem) may have one or more of the following tests.

Computed tomography (CT) scan

The CT scan uses x-rays to make detailed cross-sectional images of your body. Unlike a regular x-ray, CT scans can show the detail in soft tissues (such as internal organs). This scan can help tell if any lymph nodes or organs in your body are larger than normal.

CT-guided needle biopsy: In some cases, CT scans can also be used to guide a biopsy needle precisely into a lymph node. A small sample of the node is then removed and looked at with a microscope. A needle biopsy can’t diagnose CD by itself, but it can sometimes help diagnose or exclude other diseases that can cause large lymph nodes.

Magnetic resonance imaging (MRI)

MRI is not used as often as CT scans for lymph node problems, but if your doctor is concerned about areas near your spinal cord or brain, MRI is very useful for looking at these areas.

Like CT scans, MRI scans show detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays.

Chest x-ray

This test might be done if you’re having breathing problems, to find out if there are enlarged lymph nodes in your chest (usually in the center part of the chest between the lungs, the mediastinum)..


Ultrasound uses sound waves and their echoes to create pictures of internal organs or masses.

Ultrasound can be used to look at lymph nodes near the surface of your body or to look inside your abdomen for enlarged lymph nodes or organs such as the liver and spleen. It can also show kidneys that have become swollen because the outflow of urine has been blocked by enlarged lymph nodes. (It can’t be used to look at organs or lymph nodes in the chest because the ribs block the sound waves.)

Positron emission tomography (PET) scan

PET scans are helpful in finding small collections of fast-growing cells that might not be visible on a CT scan. PET is not often used to diagnose CD, but sometimes it can help the doctor determine the cause of enlarged lymph nodes.

For a PET scan, you are injected with a slightly radioactive form of sugar, which collects mainly in cancer cells. A special camera is then used to create a picture of areas of radioactivity in the body. The picture is not detailed like a CT or MRI scan, but a PET scan can look for possible areas of cancer spread in all areas of the body at once.

Some newer machines can do both a PET and CT scan at the same time (PET/CT scan). This lets the doctor see areas that “light up” on the PET scan in more detail.

Gallium scan

For this test, you are injected with a solution containing slightly radioactive gallium. It is attracted to lymph tissue in the body. A few days later a special camera is used to detect the radioactivity, showing the location of the gallium. A gallium scan can sometimes find unsuspected sites of CD disease, but it is not always reliable since the gallium might not be taken up by all of the lymph nodes affected by CD.

This test is not used as much now as in the past, as many doctors do a PET scan instead.

Lymph node biopsy

A doctor might suspect you have Castleman disease based on your symptoms or the results of exams or tests, but it can only be diagnosed by removing an enlarged lymph node and examining it under the microscope. This procedure is called a biopsy. Different types of biopsies can be used, based on where the lymph node is.

Excisional or incisional biopsy: If the lymph node is near the skin surface, a surgeon can often remove the node using local anesthesia (numbing medicine). The surgeon cuts the skin over the enlarged lymph node, removes the node, and then stitches the cut closed.

  • If the procedure removes the entire lymph node, it is called an excisional biopsy.
  • If only part of the node is removed, it is called an incisional biopsy.

If the lymph node is in the chest or the abdomen, the surgeon might need to make a large incision to get into either of these places. This type of surgery might require general anesthesia (where you are in a deep sleep), but it might be needed to learn why the lymph node is enlarged.

Sometimes, lymph nodes in the chest can be removed by mediastinoscopy. In this procedure, a small cut is made in the front of the neck and a thin, hollow, lighted tube (called a mediastinoscope) is inserted behind the sternum (breast bone) and in front of the windpipe to look at the area. Special instruments can be passed through this tube to remove all or part of a lymph node.

The same type of procedure can be used to sample lymph nodes in the abdomen. In this case, the test is known as laparoscopy. The doctor makes a small cut in the abdomen and inserts a thin, hollow, lighted tube (called a laparoscope) and other instruments to look at the area and remove all or part of a lymph node.

Fine needle aspiration (FNA) or core needle biopsy: Sometimes lymph nodes are biopsied by putting a hollow needle into the node to remove a small amount of tissue. In a fine needle aspiration (FNA) biopsy, the doctor uses a very thin needle to withdraw (aspirate) a small amount of tissue from the enlarged node. For a core needle biopsy, the doctor uses a larger needle to remove a slightly larger piece of tissue.

Doctors have found that diagnosing CD by needle biopsy is sometimes possible, but biopsy methods that remove larger samples of tissue are usually recommended because they are thought to be more accurate.

Lab tests of biopsy samples

No matter what procedure is used to take a biopsy, the cells from the biopsy are then sent to a lab. Using a microscope, a doctor called a pathologist looks at them and might do other tests. Since CD is so rare, the pathologist might ask another pathologist with special training in diagnosing blood and lymph node diseases (called a hematopathologist) to look at the biopsy.

Sometimes it’s hard to tell if the lymph node is affected by CD or by lymphoma. In these cases, other tests might be done on the lymph node tissue to help figure this out. Some tests look at the proteins on the surface of the cells, while others look for gene or chromosome changes within the cells. Examples of these lab tests include:

  • Immunohistochemistry
  • Flow cytometry
  • Cytogenetics
  • Fluorescent in situ hybridization (FISH)
  • Polymerase chain reaction (PCR)

These tests, are described in more detail in Non-Hodgkin Lymphoma.

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Last Revised: February 2, 2018

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