Diagnosis
If your child has any of the previously mentioned symptoms, the doctor will conduct a physical and neurological exam and ask questions about your child's medical history. If the doctor suspects neuroblastoma, he or she may recommend any of the following procedures:
Blood/Urine Tests
The doctor will measure the levels of homovanillic acid (HVA) and vanillylmandelic acid (VMA) in your child's urine. Normally, nerve cells release hormones called catecholamines (dopamine, epinephrine, norepinephrine) into the blood in response to stress. These hormones are broken down into metabolites (such as HVA and VMA) and expelled in the urine. Higher than normal amounts of cathecolamines in your child’s blood or VMA/HVA in your child's urine may indicate neuroblastoma. The doctor may also recommend a complete blood count (CBC), blood chemistry test, and 24-hour urine test to monitor your child's overall health and organ function.
Ultrasound
Ultrasounds bounce sound waves off of your internal organs in order to create echoes that form a picture. Ultrasounds can help doctors detect masses in the abdomen and determine the presence, size, shape, and site of a tumor. Doctors often use this test to help diagnose infants because it is a very simple procedure that requires no anesthesia or radiation.
Computed Tomography (CT) Scan
CT scans use X-rays to produce an image of your body. A special dye may be injected into your child’s veins and he/she may be asked to drink a special fluid in order to make the internal organs stand out. A CT scan reveals the presence of tumors and whether or not the cancer has spread to other parts of the body.
Magnetic Resonance Imaging (MRI) Scan
MRI scans use radio waves and a strong magnet to create clear and detailed images of body parts. Radio waves are absorbed by the body and then released in a certain pattern, which is translated by a computer in order to show "slices" of the body. A special substance called gadolinium is injected into your child’s veins and collects around cancer cells that show up brighter in the picture. An MRI scan is more detailed than a CT scan and can help the doctor better determine exactly where the cancer has spread. The doctor may recommend also an MRI scan to look at tumors in certain parts of the body, such as the head, neck, brain, and spinal cord.
Metaiodobenzylguanidine (MIBG) Scan
MIBG scans use radioactive substances to find tumors that affect the nervous system. A substance called radioactive MIBG is injected into your child’s veins. This substance is very similar to norepinephrine, a hormone normally released by the nerve cells. It is taken up by neuroendocrine cells like neuroblastoma cells and causes them to light up on special imaging. This helps the doctor determine the exact extent and location of the cancer. Generally, MIBG is injected 24 to 48 hours prior to the scan, and an iodine solution, given orally to the child, is started 24 hours prior to the injection and continued for several days.
Positron Emission Tomography (PET) Scan
PET scans are nuclear medical imaging that produce three-dimensional images of functional organs in the body. A radioactive sugar-based substance is injected into your child’s veins; this substance collects in cancerous (malignant) cells in the patient's body. The doctor then uses a PET scanner to detect these areas of radioactivity and to find the exact location of cancer in the patient's body. This type of scan is usually used for children with neuroblastoma whose tumor cannot be detected by an MIBG scan.
Bone Scan
A bone scan uses nuclear medical imaging that detects certain abnormalities in bone. A radioactive substance is injected into your child’s veins and collects in areas of bone with cancer. The doctor may order a bone scan to detect bone damage caused by cancer spreading to the bones. A bone scan can show all of the bones of the body and find small areas of cancer spread and bone damage not seen on plain X-rays.
Biopsy
A biopsy is performed to confirm the diagnosis of neuroblastoma and obtain tumor tissue for additional testing. The doctor will remove a tissue sample from the tumor and have it examined by a pathologist under a microscope. Doctors most commonly perform incisional or needle biopsies for neuroblastoma. In an incisional biopsy, the doctor removes a piece of the tumor with a surgical scalpel. In a needle biopsy, the doctor extracts a tissue sample from the tumor using a thin, hollow needle. In some cases, depending on where the tumor is located and how big it is, the whole tumor is removed at the same time a biopsy is done.
Bone Marrow Aspiration & Biopsy
In this test, the doctor uses a thin needle to extract a sample of bone marrow tissue from the hip bone, and sends it to a lab to be examined under a microscope. Doctors commonly perform this test if neuroblastoma is suspected, as this disease often spreads to the bone marrow.
