The First Clues: Signs and Symptoms of Neuroblastoma
The diagnostic process for neuroblastoma begins when a child shows signs that something is wrong. Because these tumors can grow in various locations such as the abdomen, chest, or neck, symptoms can be diverse and often stem from the tumor pressing on nearby tissues or spreading to other parts of thebody.
Abdominal Lumps and Swelling
The most frequent sign is a noticeable lump or a general firmness in the abdomen. This mass often originates in the adrenal glands, located on top of the kidneys, and can cause the belly to appear swollen. In infants, a particularly large tumor may even lead to breathing difficulties.
Changes Around the Eyes
Neuroblastoma that has spread can cause distinct changes around the eyes. This may include dark circles that resemble "black eyes," which are caused by cancer cells in the bones of the eye sockets. In other cases, a tumor growing behind the eye can cause it to bulge forward. A different condition, Horner syndrome, can result from a tumor affecting certain nerves, leading to a droopy eyelid and a smaller pupil on one side of the face.
Bone Pain and Systemic Symptoms
When the cancer metastasizes to the bones or bone marrow, a child might experience persistent bone pain, which can cause limping or a refusal to walk. If cancer infiltrates the bone marrow, it disrupts the production of blood cells. This can lead to unexplained fevers, fatigue from anemia, easy bruising, or the appearance of tiny, flat, red spots under the skin known as petechiae.
Neurological Problems
In some instances, a tumor growing along the spine can press on the spinal cord. This compression can cause weakness in the legs, problems with walking, or even paralysis. A much rarer but highly specific sign is opsoclonus-myoclonus syndrome, a condition characterized by rapid, uncontrolled eye movements and jerky muscle spasms that strongly suggests an underlying neuroblastoma.
The Initial Consultation: Medical History and Physical Exam
If neuroblastoma is suspected, the diagnostic journey starts with a thorough medical evaluation. This first appointment is essential for gathering the information that will guide all subsequent testing.
Reviewing Your Child's Health Story
The doctor will ask for a detailed history of your child's symptoms, including when they first appeared and how they may have changed. Be prepared to discuss any lumps you have noticed, changes in energy levels, unexplained fevers, or complaints of pain. Information about appetite, weight loss, and general well-being is also critical.
The Head-to-Toe Physical Exam
During the physical exam, the doctor will carefully assess your child for clues. This includes gently feeling the abdomen and neck for masses or swelling and checking blood pressure, as some neuroblastoma tumors release hormones that can raise it. The doctor will also inspect the skin for any unusual lumps and examine the eyes for signs like bruising, bulging, or a droopy eyelid.
Assessing Neurological Function
A key part of the exam involves checking your child's neurological health. The doctor will test muscle strength, reflexes, balance, and coordination to look for any weakness, especially in the legs, which could indicate a tumor is compressing the spinal cord.
Discussing Family History
Although it is uncommon, neuroblastoma can sometimes be hereditary. The physician will inquire about the health history of close relatives to see if anyone has been diagnosed with neuroblastoma or related cancers. This helps determine if a genetic component needs to be considered in your child's care.
Lab Tests: Finding Clues in Blood and Urine
Following the physical exam, laboratory tests on blood and urine samples are performed to look for specific chemical markers of neuroblastoma. These substances help confirm the diagnosis and provide more information about the tumor.
Urine Tests for HVA and VMA
Neuroblastoma cells frequently produce high levels of hormones known as catecholamines. As the body breaks down these excess hormones, it creates waste products called homovanillic acid (HVA) and vanillylmandelic acid (VMA). Finding elevated levels of HVA and VMA in a urine sample is a strong indicator of neuroblastoma. This test is also used throughout treatment to monitor how the cancer is responding.
Blood Test for Ferritin
A blood test is used to measure ferritin, a protein that stores iron in the body. Neuroblastoma cells have a tendency to produce and release large quantities of this protein, so a high ferritin level can serve as another piece of evidence. However, since other conditions like inflammation can also raise ferritin levels, doctors interpret this result in the context of all other findings.
Blood Test for Lactate Dehydrogenase (LDH)
Doctors also check the blood for an enzyme called lactate dehydrogenase (LDH). This enzyme is released into the bloodstream when cells are damaged or die. Because cancer involves rapid cell turnover, a large or aggressive tumor can cause a significant rise in LDH. High levels can help doctors estimate the overall amount of cancer in the body.
Imaging Tests: Seeing the Tumor
To get a clear picture of what is happening inside your child's body, doctors use a variety of imaging technologies. These scans create detailed images that allow the medical team to locate the tumor, determine its size, and see if it has spread.
Computed Tomography (CT) Scan
A CT scan uses specialized x-ray equipment to generate detailed, cross-sectional images of the body. It is highly effective for examining a primary tumor in the abdomen, chest, or neck. The images reveal the tumor's exact size and its relationship to nearby organs and blood vessels, which is critical information for surgical planning.
Magnetic Resonance Imaging (MRI) Scan
An MRI scan uses powerful magnets and radio waves to create clear images of the body's soft tissues. It is the preferred test if a tumor is suspected near the spine, as it can show with great precision whether the tumor is compressing the spinal cord—a condition that requires immediate medical attention.
MIBG Scan
The MIBG scan is a specialized nuclear imaging test that is highly specific for neuroblastoma. It involves injecting a small, safe amount of a radioactive substance called MIBG, which is readily absorbed by neuroblastoma cells. A special camera then scans the body to see where the MIBG has accumulated, causing any tumors to "light up." This powerful scan is excellent for confirming the diagnosis and detecting cancer that has spread to distant sites.
Biopsy and Bone Marrow Tests: Confirming the Diagnosis
While imaging and lab results can point strongly to neuroblastoma, a definitive diagnosis requires examining the tumor cells directly. This is accomplished with a biopsy and bone marrow tests, which provide the crucial information needed to plan the most effective treatment.
The Tumor Biopsy
In a biopsy, a surgeon removes a small piece of the tumor so it can be sent to a pathologist for microscopic examination. This procedure is essential to confirm that the cells are indeed neuroblastoma and to provide tissue for further analysis. Depending on the tumor's location and size, the sample may be obtained through a small incision or a more extensive open surgery.
Bone Marrow Aspiration and Biopsy
Because neuroblastoma frequently spreads to the bone marrow, doctors must perform this procedure to "stage" the disease—that is, to determine exactly how far it has spread. Using a thin, hollow needle, a doctor draws out a small amount of liquid marrow (aspiration) and a tiny core of solid bone (biopsy) from the back of the hip bone. Your child will receive medication to remain comfortable and sleepy throughout the procedure.
Laboratory Analysis and Risk Grouping
The collected tumor and bone marrow samples are sent to a specialized lab for detailed evaluation. First, a pathologist examines the cells' appearance, or histology, to help predict the tumor's likely behavior. Next, the samples undergo molecular testing to look for specific genetic changes in the cancer cells, such as amplification of the MYCN gene. This biological information, combined with the cancer's stage, allows the medical team to assign a risk group (low, intermediate, or high risk). This risk classification is the single most important factor in creating a personalized and effective treatment plan for your child.
