How is Neuroblastoma Diagnosed?
Symptoms of Neuroblastoma mimic common childhood illnesses.
Since neuroblastoma is rare, pediatricians often miss its diagnosis initially. Children can present with a variety of symptoms such as irritability and low-grade fever – symptoms that mimic common illnesses and viruses, or diseases such as juvenile rheumatoid arthritis that cause joint pain. The symptoms a child experiences are typically related to where the tumor originates and if the cancer has spread. For example, children with a tumor in the abdomen may have a swollen abdomen, constipation, vomiting, or diarrhea. A child with a tumor on the spine may stop crawling or walking, or may have weakness or paralysis. A tumor in the chest may cause breathing difficulties. A child whose disease has spread to bones may have black eyes, bone pain, bruises, fever, paleness, and may limp or stop crawling or walking. A tumor in the neck may cause different pupil size and sweating or redness on one side of the face ("Horner's syndrome"). In very rare cases, a child has an immune response known as opsoclonus myoclonus syndrome, or OMS, causing rapid eye movements and jerky muscle motions (2 percent of all neuroblastoma cases).
Neuroblastoma can be difficult to diagnose.
Once a pediatrician or other doctor rules out alternative diseases and conditions and suspects cancer, the child is referred to a pediatric oncologist to determine diagnosis.
Neuroblastoma can be difficult to diagnose because it is one of several small round blue cell tumors (such as acute leukemia, Ewing's sarcoma, Wilm's tumor, and rhabdomyosarcoma) that look identical under a microscope. To make a definitive diagnosis, doctors evaluate a variety of scans, the results of blood and urine tests, as well as biopsies from the primary tumor or other sites of disease, such as the lymph nodes or bone marrow.
A biopsy of the primary tumor is preferred and considered optimal because certain information about the disease can only be derived from the primary tumor before chemotherapy treatments begin. The pathologist looks at the biopsy of the primary tumor under a microscope and grades the tumor as favorable or unfavorable by the structure and form of the cells (called histology or biology). Biopsy samples may be a prerequisite for some treatment protocols. If a biopsy of the primary tumor is not feasible, a definite diagnosis of neuroblastoma can be made from a biopsy of tissue from metastases (such as lymph nodes or bone marrow) if certain "markers" or in the urine known as "catecholamines" are also elevated.
Your child's doctor will likely recommend many or all of the following tests and scans:
• Urine tests
• Blood tests
• CT scan
• PET scan
• Bone scan
• MIBG scan
• Bone marrow aspiration and biopsy
• Lumbar puncture (LP) is NOT performed if NB is suspected
These tests and scans are required to determine the location and size of the primary tumor, the extent of spread (stage), and elevated disease markers that may be present in blood or urine. Lumbar puncture may cause spread of neuroblastoma into the CNS (spinal canal or brain), therefore it’s typically not performed if neuroblastoma is suspected. Additional tests will be performed for baseline organ function.