Tests For Neuroblastoma

Neuroblastomas are usually found when a child is brought to the doctor because of signs or symptoms he or she is having. If a tumor is suspected, tests will be needed to confirm the diagnosis.

Medical history and physical exam

If your child has signs or symptoms that might be caused by a neuroblastoma (or another tumor), the doctor will ask about the symptoms and how long they have been present. The doctor might also ask if there is any history of possible risk factors, such as a family history of neuroblastoma.

The doctor will examine your child for possible signs of a neuroblastoma and other health problems. For example, the doctor may be able to see or feel an abnormal mass or swelling. The doctor might feel to see if the child has lumps or bumps under the skin and examine your child's eyes closely. They might also look at your child's blood pressure because sometimes neuroblastoma cells can make hormones that cause high blood pressure. Neuroblastomas can sometimes grow close to the spinal cord, which can affect movement and strength in the child’s arms and legs, so the doctor will pay close attention to these.

Some signs that could be caused by neuroblastoma, such as fever and enlarged lymph nodes, are much more likely to be caused by an infection, so the doctor might look for other signs of infection at first.

Lab and imaging tests

If the history and exam suggest a child might have a neuroblastoma (or another type of tumor), more tests will be done. These could include blood and urine tests, imaging tests, and biopsies. These tests are important because many of the symptoms and signs of neuroblastoma can also be caused by other diseases, such as infections, or even other types of cancer.

Blood and urine catecholamine tests

The body makes many different types of hormones. Sympathetic nerve cells normally release hormones called catecholamines, such as epinephrine (adrenaline) and norepinephrine, which enter the blood and eventually break down into smaller pieces, called metabolites. The metabolites normally pass out of the body in urine. When epinephrine and norepinephrine are broken down by the body, the two most common metabolites made are:

  • Homovanillic acid (HVA)
  • Vanillylmandelic acid (VMA)

Neuroblastoma cells can also make these catecholamines. These 2 catecholamine metabolites can be measured in blood and urine. In most cases, neuroblastoma cells make enough catecholamines to be detected by blood or urine tests. If neuroblastoma cells are making catecholamines, the amount of HVA and VMA in urine or blood will be higher than expected.

If neuroblastoma is suspected or has been found, your child’s doctor will probably order blood tests to check blood cell counts, liver and kidney function, and the balance of salts (electrolytes) in the body. A urinalysis (urine test) may also be done to further check kidney function.

Imaging tests

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

  • To help find out if a suspicious area might be cancerous
  • To learn how far cancer has spread
  • To help determine if treatment has been effective

If neuroblastoma is highly suspected, the most common imaging test to have first is usually an MRI or CT scan.  If your child is diagnosed with neuroblastoma, they will have an MIBG scan as well. Most children who have or might have neuroblastoma will have one or more of these tests, but might not need all of these tests.

Children with neuroblastoma are often very young, so it can be hard to do some of these tests because the child might need to hold very still. Depending on your child's age and the imaging test that they will have, they might get medicines that are a kind of anesthesia or sedation to help them keep still.

Ultrasound (sonogram)

Ultrasound might be one of the first tests done in very young children if a tumor is suspected, because it is fairly quick and easy, it does not use radiation, and it can often give the doctor a good view inside the body, especially in the abdomen (belly). Ultrasounds are usually not done if the child has already had an MRI or CT scan.

For this test, your child lies on a table (or sits on your lap) while a small wand called a transducer is placed on the skin over the belly (which is first lubricated with gel). The wand gives off sound waves and picks up the echoes as they bounce off organs. The echoes are converted by a computer into a black and white image on a screen. The test is not usually painful, but it might cause some discomfort if the transducer is pressed down hard on the belly.

Ultrasound is used most often to look for tumors in the abdomen. (It’s not used to look in the chest because the ribs block the sound waves.)

Magnetic resonance imaging (MRI) scan

MRI scans provide detailed images of soft tissues in the body. These scans are very helpful in looking at the brain and spinal cord. They may be slightly better than CT scans for seeing the extent of a neuroblastoma tumor, especially around the spine.

MRI scans use radio waves and strong magnets to create the images instead of x-rays, so there is no radiation. A contrast material called gadolinium may be injected into a vein before the scan to better see details.

MRI scans can take up to an hour. For most MRI machines, your child has to lie inside a narrow tube, which is confining and can be distressing. Newer, more open MRI machines may be an option in some cases, but they still require the child to stay still for long periods of time. The MRI machine also makes loud buzzing and clicking noises that may be disturbing. Younger children and children who will not be able to be still for a long period of time are often given medicine to help keep them calm or even asleep during the test.

Computed tomography (CT or CAT) scan

CT scans are often used to look for neuroblastoma in the abdomen, pelvis, and chest.

Before the test, your child may be asked to drink a contrast solution and/or get an IV (intravenous) injection of a contrast dye. This helps better outline structures in the body.

Younger children or children that might not be able to hold still may be sedated (given medicine to make them sleepy) before the test to reduce movement and help make sure the pictures come out well.

CT-guided needle biopsy: CT scans can also be used to help guide a biopsy needle into a tumor. It is not as common for children to have a needle biopsy if neuroblastoma is suspected because the amount of the sample collected might not be enough for all of the tumor tests that are needed.

MIBG scan

This test is often an important part of finding out how far a child's neuroblastoma has spread. It is often done after a CT scan or MRI has already been done. This scan uses a form of the chemical meta-iodobenzylguanidine (MIBG) that contains a small amount of radioactive iodine. MIBG is similar to norepinephrine, a hormone made by sympathetic nerve cells. It is injected into a vein and travels through the blood, and in most patients it will attach to neuroblastoma cells anywhere in the body. Between 1 and 3 days later, the body is scanned with a special camera to look for areas that picked up the radioactivity. This helps doctors know where the neuroblastoma is and if it has spread to the bones and/or other parts of the body.

MIBG scans can be repeated after treatment to see if the tumors are responding well. It is also good to know if the tumor takes up the MIBG because in some cases, this radioactive molecule can be used at higher doses to treat the neuroblastoma (see Radiation Therapy for Neuroblastoma). The thyroid gland can also absorb MIBG, so a medicine containing iodine is sometimes given before and during the test to protect the thyroid.

Bone scan

A bone scan can help show if a cancer has spread to the bones, and can provide a picture of the entire skeleton at once. Neuroblastoma often causes bone damage, which a bone scan can find. This test used to be done routinely, but in many centers it has been replaced by use of MIBG or PET scans.  This test might be done after an MIBG scan, depending on those results.

For this test, a small amount of low-level radioactive material (technetium-99) is injected into a vein. (The amount of radioactivity used is very low and will pass out of the body within a day or so.) The substance settles in areas of damaged bone throughout the skeleton over the course of a couple of hours. Your child then lies on a table for about 30 minutes while a special camera detects the radioactivity and creates a picture of the skeleton. Younger children may be given medicine to help keep them calm or even asleep during the test.

Areas of active bone changes attract the radioactivity and appear as “hot spots” on the skeleton. These areas may suggest cancer, but other bone diseases can also cause the same pattern. To help tell these apart, other imaging tests such as plain x-rays or MRI scans, or even a bone biopsy might be needed.

Positron emission tomography (PET) scan

For a PET scan, a radioactive substance (usually a type of sugar related to glucose, known as FDG) is injected into the blood. The amount of radioactivity used is very low and will pass out of the body within a day or so. Because cancer cells in the body are growing quickly, they absorb large amounts of the radioactive sugar. After about an hour, your child will be moved onto a table in the PET scanner. He or she will lie on the table for about 30 minutes while a special camera creates a picture of areas of radioactivity in the body. Younger children may be given medicine to help keep them calm or even asleep during the test. The picture from a PET scan is not as detailed as a CT or MRI scan, but it can provide helpful information about the whole body.

Some newer machines can do a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed appearance of that area on the CT scan.

X-rays

The doctor may order an x-ray of the chest or another part of the body as an early test if a child is having symptoms but it’s not clear what might be causing them. But the pictures might not be good enough to spot tumors.

An MIBG scan or a bone scan is usually better for looking at the bones in the rest of the body and to see if neuroblastoma has spread to the bones.

A standard chest x-ray may be done if a child is having trouble breathing, but a CT or MRI scan of the chest can show more about the tumor size and location.

Biopsies

Exams and imaging tests might strongly suggest a child has neuroblastoma, but a biopsy (removing some of the tumor for viewing under a microscope and other lab testing) is usually needed to be sure. During a biopsy, the doctor removes a piece of the tumor. The biopsy samples are sent to a lab, where they are viewed under a microscope by a pathologist (a doctor with special training in identifying cancer cells). Some neuroblastomas are easily recognized when looked at by experienced doctors. But some may be hard to tell apart from other types of children’s cancers. In these cases, special lab tests must be done to show the tumor is a neuroblastoma.

In adults, biopsies are sometimes done using local anesthetic (numbing medicine), but in children they are more often done while the child is under general anesthesia (asleep). There are 2 main types of biopsies:

  • Incisional (open or surgical) biopsy: This type of biopsy is done by removing a piece of the tumor through an incision (cut) in the skin. For tumors deep in the body this may be done laparoscopically using long, thin surgical tools inserted through small cuts in the skin.
  • Needle (closed) biopsy: For this type of biopsy, a thin, hollow needle is placed through the skin and into the tumor to remove a small sample. If the tumor is deep within the body, CT scans or ultrasound can be used to help guide the needle into the tumor. Needle biopsies are not usually helpful when a child might have neuroblastoma because the amount of tumor in the sample is often not large enough to have all the special tests that are needed.

Other lab tests on neuroblastoma samples can help determine how quickly the tumor might grow or spread in the body. What doctors learn about a child's neuroblastoma from these tests can help determine what treatments might work the best. Some of these tests are described in Neuroblastoma Stages and Prognostic Markers.

Bone marrow aspiration and biopsy

Neuroblastoma often spreads to the bone marrow (the soft inner parts of certain bones). If blood or urine levels of catecholamines are increased, then finding cancer cells in a bone marrow sample is enough to diagnose neuroblastoma (without getting a biopsy of the main tumor). If neuroblastoma has already been diagnosed by a biopsy done elsewhere in the body, bone marrow tests are done to help determine the extent of the disease.

A bone marrow aspiration and biopsy are usually done at the same time. In most cases the samples are taken from the back of both of the pelvic (hip) bones.

Even when the area is numbed with local anesthetic, these tests can be painful, so in most cases the child is also given other medicines to reduce pain or even be asleep during the procedure.

For a bone marrow aspiration, a thin, hollow needle is inserted into the bone and a syringe is used to suck out a small amount of liquid bone marrow.

A bone marrow biopsy is also done. A small piece of bone and marrow is removed with a slightly larger needle that is pushed down into the bone. Once the biopsy is done, pressure is applied to the site to help stop any bleeding.

Samples from the bone marrow are sent to a lab, where they are looked at and tested for the presence of cancer cells. You can read more about testing tissue samples in Testing Biopsy and Cytology Specimens for Cancer.

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.

Brodeur GM, Hogarty MD, Bagatell R, Mosse YP, Maris JM. Neuroblastoma. In: Pizzo PA, Poplack DG, eds. Principles and Practice of Pediatric Oncology. 7th ed. Philadelphia Pa: Lippincott Williams & Wilkins; 2016:772–792.

Dome JS, Rodriguez-Galindo C, Spunt SL, et al. Pediatric solid tumors. In: Neiderhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 5th ed. Philadelphia, PA. Elsevier: 1804-1847.

Last Medical Review: March 19, 2018 Last Revised: March 19, 2018

American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.