People with Castleman disease (CD) may see their doctor because they have felt a lump that hasn't gone away, they develop some of the other symptoms listed below, or they just don't feel well and go in for a checkup.

CD is rare, and its symptoms are often like those caused by other diseases (including infections and lymphomas), so doctors may 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.

Signs and symptoms of CD

For most people with the localized form of CD, an enlarged lymph node, usually inside the chest or abdomen, is often the only sign of the disease. If the enlarged node is near the skin it might be seen or felt, but if it is in the chest or abdomen it may not be noticed until it grows large enough to cause other symptoms.

If the enlarged node is in the chest, it may press on the windpipe. A person may have trouble breathing, a cough, or a feeling of fullness in the chest. CD in the abdomen can cause trouble eating, pain, or just a feeling of fullness. In general, most people with localized CD feel well otherwise, although some may also have some of the other symptoms listed below.

People with multicentric CD have more than one area of enlarged lymph nodes. The involved nodes may be in the chest or abdomen, but multicentric CD disease often affects lymph nodes in the groin, the underarm area, and on the sides of the neck, which can often be seen or felt as lumps under the skin.

Multicentric CD can also affect lymphoid tissue of internal organs, causing the liver, spleen, or other organs to enlarge. Enlarged organs may be seen or felt as masses under either side of the rib cage. They may also add to problems eating or a sense of fullness in the abdomen.

In addition, people with either type of CD may have other symptoms. But these symptoms occur much more often in people with multicentric than localized CD.

The most common include:

Fever

Weakness and fatigue (tiredness)

Night sweats (that soak the sheets)

Weight loss

Loss of appetite

Nausea and vomiting

Nerve damage that leads to numbness and weakness (neuropathy)

Leg swelling (edema)

Skin rashes

Amyloidosis, a condition where abnormal proteins build up in tissues around the body, can occur in CD. This can lead to kidney damage, heart damage, nerve damage, and intestinal problems, mainly diarrhea. If the CD is successfully treated, the amyloidosis often improves or even goes away.

Anemia (low red blood cell counts) is very common in multicentric CD, and can lead to problems with weakness and shortness of breath.

Medical history and physical exam

If your symptoms suggest you might have a lymph node problem such as CD, your doctor will want to get a thorough medical history, including information about your 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.

The doctor may also order blood tests to check for infections or other problems. Several types of blood tests may be abnormal in people with CD.

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

Imaging tests

Imaging tests use x-rays, magnetic fields, or radioactive particles to produce pictures of the inside of the body. These tests may be done for a number of reasons, including looking for enlarged lymph nodes or other problems that might be causing symptoms, looking for enlarged nodes in other parts of the body, and helping determine whether treatment has been effective.

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 is an x-ray test that produces 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 enlarged.

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 may be asked to drink 1 or 2 pints of a contrast agent. This helps outline the intestine so that certain areas are not mistaken for tumors. You may 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 to the dye and get hives or, rarely, more serious reactions like trouble breathing and low blood pressure. You can be given medicine to prevent and treat allergic reactions. 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.

CT scans take longer than regular x-rays because you need to lie still on a table while they are being done. During the test, the table slides in and out of the scanner, a ring-shaped machine that completely surrounds the table. You might feel a bit confined by the ring you lie within while the pictures are being taken.

CT scans can also be used to guide a biopsy needle precisely into an enlarged lymph node. For this procedure, called a CT-guided needle biopsy, you remain on the CT scanning table while a doctor moves a biopsy needle through the skin and toward the location of the lymph node. CT scans are repeated until the needle is within the lymph node. A fine needle biopsy sample (tiny fragments of tissue) or a core needle biopsy sample (a larger cylinder of tissue) is removed to be looked at under a microscope. While a needle biopsy cannot accurately diagnose CD by itself, 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.

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 they take longer than CT scans – often up to an hour. You have 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 may be done to find out whether there are enlarged lymph nodes in your chest – usually in the center part between the lungs called the mediastinum.

Ultrasound: Ultrasound uses sound waves and their echoes to produce a picture 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 emits 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 detect 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 may not be visible on 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. 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 of 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. CD cells don't take up the sugar as much as cancer cells, but they do seem to take it up more than normal cells. The picture from a PET scan is not finely 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 may 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 may do a PET scan instead.

Lymph node biopsy: A doctor may suspect you have Castleman disease based on your symptoms or the results of exams or tests, but it can only really be diagnosed by removing the enlarged lymph node and examining it under the microscope. This procedure is called a biopsy. Different types of biopsies may 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 makes a small incision (cut) over the enlarged lymph node, removes the node, and then stitches the incision 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, then the surgeon may need to make a large incision to get into either of these places. This is more like major surgery but it may be needed to know what is causing the lymph node to enlarge.

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 aslaparoscopy. A small cut is made in the abdomen and a thin, hollow, lighted tube (called a laparoscope) is inserted to allow the doctor 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, hollow needle attached to a syringe 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 diagnosis of 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 who is specially trained to diagnose disease), who studies the size and shape off the cells and how they are arranged. Since this disease is so rare, the pathologist may ask another pathologist with additional training in diagnosing blood and lymph node diseases (called a hematopathologist) to look at the biopsy. Sometimes it is hard to tell if the lymph node is affected by CD or by lymphoma. In these cases, other tests may be done on the lymph node tissue.

Immunohistochemistry: In this test, a part of the biopsy sample is treated with special man-made antibodies that will attach only to cells that contain specific molecules on their surface. These antibodies cause color changes, which can be seen under a microscope. This test may help tell whether there is CD or lymphoma in the lymph node.

Flow cytometry: Like immunohistochemistry, this test looks for certain substances on the outside surface of cells that help show what types of cells they are. But this test can look at many more cells than immunohistochemistry.

For this test, a sample of cells is treated with special antibodies that stick to the cells only if certain substances are present on their surfaces. The cells are then passed in front of a laser beam. If the cells now have antibodies attached to them, the laser will cause them to give off light, which can be measured and analyzed by a computer. Groups of cells can be separated and counted by these methods.

This test can help determine whether lymph node swelling is caused by lymphoma, some other cancer, or a non-cancerous disease like Castleman disease.