How Is Castleman Disease Diagnosed?

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 seen on an imaging 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 actual diagnosis of CD is made when doctors remove an affected lymph node and look at it under 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 the lymph nodes and other areas of the body that might 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 might 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)

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.

Instead of taking one picture like a regular x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into detailed images of the part of your body being studied.

Before the scan you might be asked to drink 1 or 2 pints of a contrast agent. This helps outline the intestine so that certain areas aren’t mistaken for tumors. You might also need an intravenous (IV) line through which a different kind of contrast dye is injected. This helps better outline structures in your body. The injection can cause some flushing (redness and warm feeling, especially in the face). Some people are allergic and get hives. Rarely, more serious reactions like trouble breathing and low blood pressure can occur. Be sure to tell your doctor if you have any allergies or have ever had a reaction to any contrast material used for x-rays. You can be given medicine to help prevent or treat allergic reactions.

A CT scanner has been described as a large donut, with a narrow table that slides in and out of the middle opening. You will need to lie still on the table while the scan is being done. CT scans take longer than regular x-rays, and you might feel a bit confined by the ring while the pictures are being taken.

CT-guided needle biopsy: CT scans can also be used to guide a hollow biopsy needle precisely into an enlarged lymph node. For this procedure, you remain on the CT scanning table while a doctor moves a biopsy needle through the skin and toward the lymph node. CT scans are repeated until the needle is within the lymph node. A small sample of the node is then removed to be looked at under 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)

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

Like CT scans, MRI scans provide detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed by the body and then released in a pattern formed by the type of body tissue and by certain diseases. A computer translates the pattern of radio waves given off by the tissues into a very detailed image of parts of the body. A contrast material might be injected just as with CT scans but is used less often.

MRI scans take longer than CT scans – often up to an hour – and are a little more uncomfortable because you have to lie inside a narrow tube, which is confining and can upset people with a fear of enclosed spaces. Newer, more open MRI machines may be another option. The MRI machine makes loud buzzing and clicking noises that you may find disturbing. Some places provide headphones or earplugs to help block this noise out.

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 called the mediastinum.


Ultrasound uses sound waves and their echoes to create pictures of internal organs or masses. For this test, a small, microphone-like instrument called a transducer is placed on the skin (which is first lubricated with a gel). It gives off sound waves and picks up the echoes as they bounce off the organs. The echoes are converted by a computer into a black and white image that is displayed on a computer screen.

Ultrasound can be used to look at lymph nodes near the surface of the 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.)

This is an easy test to have done, and it uses no radiation. For most ultrasounds, you simply lie on a table, and a technician moves the transducer over the part of your body being looked at.

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, a form of radioactive sugar (known as fluorodeoxyglucose or FDG) is injected into the blood. (The amount of radioactivity used is very low and will pass out of the body over the next day or so.) After about an hour, you are moved onto a table in the PET scanner. You lie on the table for about 30 minutes while a special camera creates a picture showing areas of radioactivity in the body.

Any cancer cells in the body will be growing quickly, so they absorb large amounts of the radioactive sugar. Although CD cells don’t take up the sugar as much as cancer cells, they do seem to take it up more than normal cells. The picture from a PET scan is not detailed like a CT or MRI scan, but it can provide helpful information about your whole body.

Often the PET scan is combined with a CT scan, which is more detailed. This helps the doctor determine if abnormal areas seen on the CT scan are CD, cancer, or something else.

Gallium scan

For this test, a solution containing slightly radioactive gallium is injected into a vein. It is attracted to lymph tissue in the body. A few days later a special camera is used 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

All biopsy specimens are looked at under a microscope by a pathologist (a doctor specially trained to diagnose disease), who studies the size and shape of the cells and how they are arranged. 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 our document Non-Hodgkin Lymphoma.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: July 7, 2014 Last Revised: May 23, 2016

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