Central nervous system neoplasms are abnormal growths that form in the brain or spinal cord, the two vital structures that control how our bodies work. These tumors can be noncancerous or cancerous, but both types may cause serious health problems if they grow large enough to press on surrounding tissues. Understanding these conditions helps patients and families navigate the complex journey from diagnosis to treatment.

Epidemiology

Central nervous system tumors represent a significant health concern affecting both adults and children across the world. Brain tumors account for approximately 85% to 90% of all primary central nervous system tumors, making them the most common type within this category.^[8]

In the United States, data from 2017 to 2021 showed that the combined incidence of brain and other CNS tumors was 6.2 cases per 100,000 people per year. The mortality rate during this period was 4.4 deaths per 100,000 people per year. For 2025, an estimated 24,820 new cases and 18,330 deaths from brain tumors and other nervous system tumors are expected in the United States alone.^[8]

Globally, the burden of these diseases is substantial. Approximately 321,476 new cases of brain and other CNS tumors were diagnosed worldwide in 2022, with an estimated 248,305 deaths occurring from these conditions.^[8] These numbers reflect the serious nature of CNS tumors and their impact on populations around the world.

The incidence of primary CNS tumors shows some demographic patterns. In general, these tumors occur more frequently in white individuals compared to Black individuals. Additionally, mortality rates are higher in men than in women, suggesting that gender may play a role in disease outcomes.^[8]

Among children, CNS tumors are the second most common type of childhood cancer. Around 4,000 new cases are diagnosed each year in children, making these tumors a major concern in pediatric oncology.^[2]

Causes

For most people diagnosed with adult brain and spinal cord tumors, the cause remains unknown. This uncertainty can be frustrating for patients and families seeking answers about why the disease developed. Researchers continue to investigate what triggers the abnormal growth of cells in the central nervous system, but definitive causes have not been identified for the majority of cases.^[1]

In children with CNS tumors, researchers believe that something may be absent or altered in the brain or spinal cord cells during normal development. Specifically, the cells of the brain and spinal cord may not grow and divide properly during critical developmental periods, though the exact mechanisms remain under investigation.^[2]

Few definitive observations have been made about environmental or occupational causes of primary CNS tumors. However, some potential risk factors have been identified through research. Exposure to vinyl chloride, a chemical used in manufacturing plastics, may be a risk factor for glioma, a type of brain tumor that develops from glial cells.^[8]

Certain viral infections have also been linked to specific types of CNS tumors. Epstein-Barr virus infection has been implicated in the development of primary CNS lymphoma, a cancer that affects the lymphatic tissue within the central nervous system.^[8]

When tumors start in another part of the body and spread to the brain, they are called metastatic brain tumors rather than primary CNS tumors. These secondary tumors are actually more common than primary brain tumors. Up to half of metastatic brain tumors originate from lung cancer, meaning the cancer started in the lungs and then spread to the brain.^[1]

Risk Factors

Certain genetic conditions that run in families can significantly increase the risk of developing a CNS tumor. These inherited syndromes involve specific chromosomal abnormalities that are passed from parents to their children. Understanding these familial connections is important for genetic counseling and early monitoring of at-risk individuals.^[8]

Several familial tumor syndromes and related chromosomal abnormalities are associated with CNS neoplasms. Neurofibromatosis type 1, caused by an abnormality on chromosome 17q11, increases the risk of developing various types of tumors including those in the nervous system. Similarly, neurofibromatosis type 2, linked to chromosome 22q12, predisposes individuals to nerve-related tumors.^[8]

Von Hippel-Lindau disease, associated with an abnormality on chromosome 3p25-26, is another genetic condition that raises the risk of CNS tumors. Tuberous sclerosis, involving chromosomes 9q34 and 16p13, can also lead to tumor development in the brain and other organs.^[8]

Li-Fraumeni syndrome, linked to chromosome 17p13, is a hereditary condition that increases the risk of multiple cancer types, including brain tumors. Turcot syndrome has two types: type 1, associated with chromosomes 3p21 and 7p22, and type 2, linked to chromosome 5q21, both of which increase CNS tumor risk. Nevoid basal cell carcinoma syndrome, involving chromosome 9q22.3, is another genetic condition associated with an elevated risk of brain tumors.^[8]

In children, researchers have found that some genetic conditions passed down from parents can give a higher risk of developing CNS tumors, though in most cases there is no known cause. This makes genetic screening and family history assessment important components of risk evaluation.^[2]

Symptoms

The signs and symptoms of adult brain and spinal cord tumors vary greatly from one person to another. What one patient experiences may be completely different from another patient’s symptoms. This variability depends largely on where the tumor is located in the central nervous system and how large it has grown.^[1]

General signs and symptoms that may occur with brain tumors include persistent headaches, which can be particularly troubling in the morning or may improve after vomiting. Seizures, which are episodes of abnormal electrical activity in the brain causing involuntary movements or changes in consciousness, are also common. Visual changes, such as blurred vision or loss of peripheral vision, may develop as the tumor affects areas of the brain responsible for sight.^[8]

Nausea and vomiting can occur, especially when the tumor increases pressure inside the skull. Changes in personality, mood, ability to focus, or behavior may be noticed by family members before the patient recognizes these changes themselves. Weakness in certain parts of the body, problems with balance and coordination, and difficulties with speech or hearing can all signal that a tumor is affecting specific brain regions.^[7]

Morning headaches or headaches that go away after vomiting are particularly concerning symptoms. Loss of appetite and frequent nausea can significantly impact a patient’s quality of life and nutritional status. Some patients experience seizures as their first symptom, which can be frightening and may lead to emergency medical evaluation.^[7]

When a tumor grows into or presses on an area of the brain, it may stop that part of the brain from working the way it should. Both benign and malignant brain tumors cause symptoms because they occupy space in the skull, which is a rigid structure that cannot expand to accommodate the growing mass.^[1]

Some brain tumors are discovered when they are very small because they cause symptoms that patients notice right away. These tumors may be located in areas of the brain that control critical functions like speech or movement. Other brain tumors grow very large before they are found because they develop in parts of the brain that are less active and their growth does not immediately interfere with obvious functions.^[4]

Prevention

Unfortunately, because the cause of most CNS tumors is unknown, there are no proven strategies to prevent these tumors from developing in most people. Unlike some cancers where lifestyle modifications can reduce risk, primary brain and spinal cord tumors do not have well-established preventive measures.^[1]

For individuals with known genetic syndromes that increase the risk of CNS tumors, regular monitoring and genetic counseling may help with early detection, though these measures do not prevent tumor development. Families with a history of certain hereditary cancer syndromes should consult with genetics specialists to understand their risks and develop appropriate screening plans.^[8]

Avoiding known environmental risk factors, when possible, may help reduce risk in some cases. For example, limiting exposure to vinyl chloride and other potentially harmful chemicals in occupational settings could theoretically lower the risk of certain types of brain tumors, though the evidence is limited.^[8]

Pathophysiology

Central nervous system tumors develop when abnormal cells form in the tissues of the brain or spinal cord. These tumors are created by the abnormal growth of cells that may begin in different parts of the central nervous system. The brain and spinal cord together make up the central nervous system, which serves as the body’s control center for all functions.^[1]

The central nervous system is responsible for sending, receiving, and processing information throughout the body, controlling how the body functions. When tumors grow in this system, they can disrupt these vital communication pathways and cause significant symptoms even when they are not cancerous.^[2]

Tumors in the CNS may be classified as either benign, meaning they do not contain cancer cells, or malignant, meaning cancer is present. Benign brain and spinal cord tumors grow and press on nearby areas of the brain but rarely spread into other tissues. However, even though they are not cancerous, they may recur after treatment.^[1]

Malignant brain and spinal cord tumors are likely to grow quickly and spread into other brain tissue. These cancerous tumors can invade and destroy healthy brain tissue as they expand. Some tumors grow slowly over months or years, while others are aggressive and expand rapidly over weeks.^[1]

When a tumor grows into or presses on an area of the brain, it may stop that part of the brain from working properly. This mechanical pressure disrupts normal brain function even before the tumor causes permanent damage. The skull is a closed, rigid space, so any growth within it creates increased pressure that affects the entire brain.^[1]

Both benign and malignant tumors can cause serious problems because of their location in the central nervous system. Even noncancerous tumors can be life-threatening if they grow in areas that control vital functions like breathing or heart rate, or if they block the flow of cerebrospinal fluid, the protective liquid that surrounds the brain and spinal cord.^[2]

Primary brain tumors rarely spread to other parts of the body outside the central nervous system, which distinguishes them from many other types of cancer. However, they can spread to other parts of the brain and to the spinal axis, meaning they can travel along the structures of the central nervous system itself.^[8]

Tumors can be classified based on the type of cells from which they originate. Gliomas develop from glial cells, which are support cells that surround and assist nerve cells in the brain. Approximately 78% of cancerous primary brain tumors are gliomas, making them the most common malignant type.^[6]

Different types of gliomas develop from different kinds of glial cells. Astrocytomas form in star-shaped glial cells called astrocytes and are the most common type of glioma. Ependymomas develop from ependymal cells near the fluid-filled spaces in the brain called ventricles. Glioblastoma, often abbreviated as GBM, represents the most aggressive form of glioma.^[6]

Researchers have identified more than 150 different types of brain tumors, each with unique characteristics and growth patterns. The diversity of these tumors reflects the complexity of the central nervous system and the many different cell types that exist within it.^[6]

Tumors are often accompanied by significant brain swelling, known as edema. This swelling can cause neurological deficits and signs of increased intracranial pressure, which is elevated pressure within the skull. Symptoms of increased intracranial pressure include headaches, nausea, vomiting, and lethargy. The edema surrounding a tumor can sometimes cause more problems than the tumor itself.^[25]