Memorial Sloan-Kettering doctors will perform a complete physical examination, as well as a number of specialized tests in order to make a diagnosis.
The first symptoms of neuroblastoma are often vague and may include fatigue and loss of appetite. As the disease progresses, symptoms will depend on the location of the tumor. A tumor in the abdomen may cause a swollen belly, stomach pain, constipation, or diarrhea. A tumor in the chest may cause breathing problems. Tumors pressing on the spinal cord may cause weakness or difficulty walking. Some children experience bone pain, and some may have unexplained “black eyes” or bulging eyes. Many of these symptoms are similar to those of other more common illnesses. Half of all neuroblastomas have already spread to other parts of the body by the time a diagnosis is made.
Because the symptoms of neuroblastoma can be similar to those of more common childhood diseases, diagnosis is often delayed. An oncologist or pathologist will generally be able to diagnose neuroblastoma after reviewing either a biopsy of the tumor or the results of bone marrow and urine tests. Other tests may also be needed to confirm the diagnosis and to measure the extent of the disease, including the stage.
The tests listed below may be used to diagnose neuroblastoma and also to find out, during treatment, how well the tumor is responding to the therapy. A number of different types of imaging scans are available, and one or more of these scans may be needed.
- Blood test — Blood tests are administered for a number of reasons. Blood may be drawn to measure white cell levels, which, if low, indicate an increased risk for infection. Other blood tests, including those that measure red cells and platelets, may indicate the need for a blood transfusion if levels are low. Several routine blood tests allow doctors to monitor the health of different body organs and the presence of neuroblastoma.
- Urine test — Urine collection usually takes place over the course of a four- to 24-hour period and is tested to measure the levels of homovanillic acid (HVA) and vanillyl mandelic acid (VMA). HVA and VMA are present in the urine normally, and their levels can rise after certain foods are eaten. However, because neuroblastoma cells secrete HVA and VMA, very high levels of these chemicals usually indicate the presence of neuroblastoma in the body.
- Biopsy — During a biopsy, a sample of cells or tissue is removed surgically and examined by a pathologist to find out if neuroblastoma or other cancer cells are present.
- Bone marrow aspiration and/or biopsy — During a biopsy or aspiration, a small amount of bone marrow is removed typically through the hip bone. A biopsy removes solid bone marrow tissue, whereas a bone marrow aspiration removes the liquid part of the marrow. Both the aspirate and the biopsy are tested for neuroblastoma.
- MIBG scan — Metaiodobenzylguanidine (MIBG) is a radioactive substance that attaches to neuroblastoma cells. During this procedure, MIBG is injected into a vein, and 24 hours later a scan is performed using what is known as a gamma camera. The MIBG causes neuroblastoma cells to light up on the scan so doctors can identify the location and extent of neuroblastoma in the body.
- CT scan — Sophisticated x-ray machines, such as those used in computed axial tomography (CT, or CAT) scans, can produce detailed images of organs, tissues, and other substances in the body. A CT scan is often used to determine the presence, location, size, and shape of a neuroblastoma tumor. The images produced by a CT scan are particularly useful prior to surgery. Once a patient has had a CT scan, it is common to continue using a CT scan for further monitoring.
- MRI scan — Sophisticated magnets, such as those used in magnetic resonance imaging (MRI) scans, can produce detailed images of organs, tissues, and other substances in the body. An MRI is used to determine the presence, location, size, and shape of a neuroblastoma tumor. It is particularly useful for scanning the brain and spinal cord, but it may also be used for other purposes. Once a patient has had an MRI scan, it is common to continue using an MRI scan for further monitoring. Unlike conventional x-rays and CT scans, MRI does not use radiation.
- Bone scan — Bone scans are used to determine whether neuroblastoma cells have spread to the bone. A radioactive substance is injected into a vein and rapidly absorbed by bone tissue. One to two hours later, the body is scanned using a gamma camera to check for the presence of neuroblastoma cells.
- PET scan — A positron emission tomography (PET) scan is sometimes performed together with CT scans to determine with greater precision the presence, location, size, and shape of a neuroblastoma tumor. During a PET scan, a radioactive substance is injected into a vein, and within hours the body is scanned.
- Ultrasound — An ultrasound (sometimes called a sonogram) involves the use of sound waves to produce images of organs, tissues, and other substances in the body. It may be used to determine the presence, location, size, and shape of a neuroblastoma tumor. In babies and young infants, ultrasound is particularly useful, since unlike CT, MRI, and PET scans, no anesthesia is necessary.
Urine screening tests are available for neuroblastoma, but these tests generally cannot distinguish low-risk from high-risk types. In newborns and infants, low-risk neuroblastoma is far more common, and generally will disappear on its own. For that reason, screening newborns or young infants for neuroblastoma in the general population is not recommended.