Neuroblastoma Overview

Neuroblastoma is a solid cancerous tumor that begins in the nerve cells of infants and young children. Neuroblastoma can start in nerve tissue of the neck, chest, abdomen, or pelvis, but it most often begins in the tissue of the adrenal glands.  The adrenal glands are located on top of both kidneys and produce hormones that help control body functions, such as heart rate and blood pressure.

Neuroblasts are immature nerve cells found in unborn babies. Normal neuroblasts mature into nerve cells or adrenal medulla cells (cells found in the center of the adrenal gland). Neuroblastoma forms when neuroblasts don’t mature properly.

Sometimes, babies are born with small masses of neuroblasts that eventually mature into nerve cells and do not become cancer. A neuroblast that does not mature can continue to grow, forming a mass called a tumor.

Neuroblastoma develops most often in infants and children younger than five years old. It can form before the baby is born and can sometimes be found during a prenatal (before birth) ultrasound examination. Most often, however, neuroblastoma is found after the cancer has spread to other parts of the body, such as the lymph nodes (tiny, bean-shaped organs that help fight infection), liver, lungs, bones, and bone marrow (the spongy, red tissue in the inner part of large bones). Taken from Cancer.net

Neuroblastoma is a solid tumor cancer of the sympathetic nervous system.

Neuroblastoma is a solid tumor-a lump or mass-originating from neural crest tissue that is part of the sympathetic nervous system (SNS). Nerves of the sympathetic nervous system run parallel along the outside of the spinal column and connect to organs. Since NB arises at the interface between the nervous system and the endocrine system (the hormone producing organs-NB is one of the few cancers that secrete hormones), it is also included in the class of neuroendocrine tumors.

The most common place for NB to originate is on the adrenal glands located above each kidney (40% of localized tumors and 60% of wide-spread disease). NB tumors can also develop in nerve tissues in the neck (1%), chest (19%), abdomen (30% non-adrenal), or pelvis (1%)-anywhere along the chain of the sympathetic nervous system.

“Neuro-” indicates origin in nerve cells, and “blast” means immature cells. Normal “neuroblasts” (baby nerve cells) begin in embryonic tissue and grow and mature into functioning nerve cells. Neuroblastoma means the immature cells reproduce forming a mass and do not develop into functioning cells (the “-oma” ending denotes a tumor). NB is not a cancer of the central nervous system (CNS) and it is not a brain cancer, but occasionally NB metastasizes to the CNS. There are over 50 kinds of pediatric cancers that fall into 12 main categories, one of which is the sympathetic nervous system cancers. NB accounts for more than 97% of all sympathetic nervous system cancers.

Neuroblastoma is a very rare cancer.

Of approximately 13,000 new cases of childhood cancer in the U.S. each year, only about 650-700 are neuroblastoma. There is similar incidence in other countries and no clear differences between ethnic groups.  About 55% of all NB patients are boys.  Understanding that NB is a rare disease is important, and that many pediatric oncologists see few NB patients in their careers.  The median age at diagnosis is about 2 years old.

Neuroblastoma differs fundamentally from adult cancers.

Neuroblastoma is fundamentally different from adult cancers – it arises in different tissues, has strikingly different characteristics, and its cause is unknown. This fact is helpful to remember when well-meaning people want to share their expertise from fighting , colon, lung, or prostate cancer-most of their experience simply does not apply to neuroblastoma.

Symptoms of Neuroblastomamimic common childhood illnesses.

Since NB is rare, most pediatricians have never seen a single case, and often the diagnosis is finally made only after a long trying period. Children may have a variety of symptoms such as irritability and low-grade fever that mimic common illnesses and viruses, or diseases such as juvenile rheumatoid arthritis that cause joint pain. Symptoms depend on where the tumor originates and if it 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.

Neuroblastoma Staging

The treatment a child receives for neuroblastoma is dependent on placement in a risk group. Risk is determined by age, tumor characteristics (pathology and genetics), and stage–the extent to which the disease has spread. Disease stage is determined according to the International Neuroblastoma Staging System (INSS), developed in 1988 and last revised in 1993 (percentages of each stage are taken from North America data on 1253 NB cases):

• Stage 1 – 21%

The tumor is confined to one area of origin and can be completely removed through surgery.  Although microscopic residual disease may remain after surgery, identifiable lymph nodes on both sides of the body are negative for NB.

• Stage 2 – 15%

2A – The tumor is confined to one area but because of size, location, or proximity to other organs, cannot be completely removed.  Identifiable lymph nodes on both sides of the body are negative for NB.

2B – The tumor is confined to one area and may or may not be completely removed.  Identifiable lymph nodes on the side of the body where the tumor is located are positive for NB, but lymph nodes on the opposite side of the body are negative for NB.

• Stage 3 – 17%

The tumor crosses the midline of the body (defined as the spine) and may or may not have spread to nearby lymph nodes; OR the tumor is confined to one area of the body with disease in lymph nodes on the other side of the body; OR the tumor is located crosses the midline with disease in lymph nodes on both sides of the body

• Stage 4 – 41% – Liam

Neuroblastoma is found in distant lymph nodes, bone marrow, bone, liver, or other organs (except in the special circumstances of Stage 4S, explained below). Indication of presence of NB cells by immunocytology alone (no visible tumor cells in bone marrow biopsy or aspirate) does not classify a child as stage 4.

• Stage 4S – 6%

Usually in infants, the tumor is confined to one area of the body, like a Stage 1 or 2 tumor, but disease has spread to only the liver, skin, or less than 10 percent of the bone marrow (no bone lesions).

Information taken from the Neuroblastoma handbook