Neuroblastoma is a rare childhood cancer that originates in the immature nerve cells called neuroblasts that are present in the fetus or embryo. Usually the condition affects children under the age of five and can even affect a baby before it is born.
Neuroblastoma is difficult to identify early on as at this stage, symptoms are vague and not unusual, such as loss of appetite or pain. The most common symptom of more advanced disease is a swelling in the abdomen that causes pain and constipation.
Diagnosis involves:
Medical history - A detailed medical history of the child is obtained. This involves asking about any family history of cancer and obtaining details of symptoms and their severity.
Physical examination - A physician may examine the child to check for an abnormal mass, lumps under the skin or high blood pressure.
If the physical exam suggests a tumor may be present, blood and urine tests, biopsy and imaging studies may be performed. These tests help the physician to rule out the many other diseases and infections that share symptoms with neuroblastoma.
Neuroblastoma can often be detected by testing the blood or urine for catecholamines as neuroblastoma cells usually produce these hormones in quantities that are high enough to be detected using these tests. The tests that are used detect the following catecholamine metabolites: homovanillic acid (HVA) and vanillylmandelic acid (VMA).
Imaging studies - Tests such as X-ray, ultrasound, computed tomography (CT) scans and magnetic resonance imaging (MRI) scans can allow the internal structures to be visualized and to help confirm whether cancer is in fact present in an area, whether or not it has spread and if treatment might be effective.
Biopsy - Although physical examination, blood tests and imaging studies may provide strong indicators that a neuroblastoma is present, the only way physicians can be sure is by way of a biopsy.
An incision may be made in the skin and a sample of the mass removed (incisional biopsy) or a hollow needle may be passed into the tumor in a process called needle (closed) biopsy. If the tumor is buried deep in the body, imaging techniques such as a CT scan or ultrasound can be used to guide the needle to the correct location.
The biopsy samples are then analysed in a laboratory to determine whether or not the tumor is in fact a neuroblastoma.
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