Skull base tumors

Skull base tumors are growths that form at the area of the skull just behind the eyes and nose, beneath the brain. The base of the skull is where important blood vessels and nerves come together with the spinal cord. The base of the skull also separates the brain from the neck.

Tumors also may be called masses, growths or lesions. These tumors can grow inside or outside the skull. They may be benign (noncancerous) or malignant (cancerous). Some skull base tumors may not cause any symptoms, but others can cause symptoms that affect your senses, such as vision or hearing, and the way that your nervous system works.

Even noncancerous skull base tumors can be dangerous. These tumors may press on the blood vessels, nerves and brain tissue in the skull base. This may lead to hearing loss, vision problems, dizziness and other issues that affect safety and well-being.

Types of skull base tumors

Types of skull base tumors are characterized by whether they are cancerous or noncancerous, and where the tumors grow in the base of the skull. Some tumors start growing somewhere else in the body and expand into the skull base.

There are many types of skull base tumors. Some of the more common types of noncancerous, also known as benign, skull base tumors include:

• Acoustic neuroma. Also called a vestibular schwannoma, this type of tumor grows on two of the nerves that help with hearing and balance. Acoustic neuromas usually grow slowly.
• Meningioma. This type of skull base tumor begins growing in the cells of the membrane lining the brain and spinal cord. This membrane is called the meninges. Rarely, meningiomas may be cancerous and grow aggressively.
• Pituitary tumor. This type of tumor forms in a pea-sized gland, called the pituitary gland, found in the skull base.
• Paraganglioma. This type of tumor usually grows in the head and neck area. While it's possible for a paraganglioma to be cancerous, it usually is not.
• Osteoma. This type of tumor is made of dense bone tissue. Osteomas grow slowly and form on the bones of the skull base. They also may be found in the sinuses.

Other rare types of benign skull base tumors include craniopharyngiomas, granular cell tumors and angiofibromas.

Malignant tumors

Some of the more common types of cancerous, also known as malignant, skull tumors include:

• Chordomas. These types of tumors tend to grow slowly, beginning in the bones of the skull base or spine. Chordomas often cause problems with vision and hearing, balance, and headaches.
• Chondrosarcomas. These tumors often develop in bones but also may grow in the nearby soft tissue called cartilage. Chondrosarcomas can occur in the bones of the skull base. These tumors usually grow slowly.
• Carcinomas. There are several kinds of skull base carcinomas, including adenoid cystic carcinomas, nasopharyngeal carcinomas, squamous cell carcinomas and adenocarcinomas. These tumors may grow in the salivary glands, the nasal cavity, the sinuses, and the head and neck area. Adenoid cystic carcinomas often grow slowly, but they tend to spread to nearby nerves and tissues.
• Olfactory neuroblastomas. These are very rare tumors that grow in the nasal cavity. They also are called esthesioneuroblastomas. These tumors can cause nosebleeds and loss of smell and may spread into the areas around the eyes and brain.

Symptoms of skull base tumors are different based on the size of the tumor, the kind of tumor, and where the tumor is growing in the skull base.

Some of the most common symptoms of skull base tumors are:

• Headaches.
• Neck pain.
• Changes in vision — blurry or double vision, or loss of vision.
• Changes in hearing — hearing loss or ringing in the ears.
• Problems with walking and balance.
• Clumsiness or other problems with coordination.
• Hoarse voice.
• Problems with breathing or swallowing.
• Changes in the sense of smell.
• Nosebleeds.

Skull base tumors may not cause any symptoms. Or the symptoms may be mild and general. Some symptoms may be headaches or problems with balance. Skull base tumors may be found by accident during imaging scans or other tests to find the cause of other symptoms.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you.

Experts aren't sure what causes most skull base tumors. Most skull base tumors seem to develop without any clear cause. It's thought that some skull base tumors, particularly acoustic neuromas, likely are caused by genetic conditions passed down in families. But several other factors also may contribute. These factors include exposure to radiation and harmful chemicals.

It's likely that a combination of factors in genes and the environment cause skull base tumors.

While experts don't know exactly what causes most skull base tumors, there are several factors that are thought to increase the risk of developing skull base tumors. The risk factors for skull base tumors include:

• Genetic conditions. Inheriting certain conditions through changes in genes can cause some types of skull base tumors. These changes in genes can cause the growth of tumor cells. Neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2) are genetic conditions that can cause acoustic neuromas and other types of skull base tissues.
• Exposure to certain chemicals. Prolonged exposure to toxic substances such as vinyl chloride, herbicides and arsenic may increase the risk of developing skull base tumors called carcinomas, particularly in the nasal and sinus areas. Cancer-causing substances such as asbestos, formaldehyde and wood dust have been linked to the development of certain skull base cancers, particularly sinonasal cancers. Exposure to high particulate air pollution — where there are solid particles in the air that may be breathed into the lungs — and radon also are associated with some tumors, especially meningiomas. These chemicals can cause mutations in the cells lining the sinuses and nasal cavity, leading to cancer.
• History of radiation exposure. Having prior radiation therapy, especially targeted at the head and neck area, may contribute to the growth of skull base tumors.
• Frequent sinus infections. Having sinus infections can be a risk factor for certain types of tumors at the skull base, particularly in the nasal cavity and paranasal sinuses.
• Hormonal changes. These are thought to play a role in the development of certain skull base tumors. It's thought that the changes in hormones during puberty may contribute to the growth of some of these tumors. Pituitary gland tumors also are affected by changes in hormones.
• Family history. Having a family history of tumors or genetic conditions such as neurofibromatosis, multiple endocrine neoplasia or other hereditary cancer syndromes increases the risk of developing skull base tumors.
• Previous history of tumors. If you've previously been diagnosed with a tumor, particularly in the head or neck, you may be at increased risk of developing a secondary skull base tumor. This may be due to factors such as previous radiation treatment or shared risk factors for tumors.
• Smoking and alcohol consumption. These factors are linked to an increased risk of certain skull base tumors, such as squamous cell carcinoma of the sinuses or the nasopharynx. The nasaopharynx is the top part of the throat that connects it to the nasal cavity.

It's important to note that having any of these risk factors doesn't mean that you will have a skull base tumor. Not everyone with these risk factors has a skull base tumor. Some people develop tumors without having any known risk factors.

Complications of skull base tumors are usually caused by the tumors growing and pressing into blood vessels, nerves and other tissues, including the brain.

Complications of the nervous system may include:

• Problems with vision.
• Hearing loss.
• Weakness or numbness in the face.
• Difficulty swallowing or speaking.
• Difficulty breathing.
• Seizures.
• Headaches.
• Cerebrospinal fluid leaks.
• Water buildup on the brain, which can increase pressure inside the skull and cause headaches, nausea and vomiting.

Other complications may include:

• Changes in hormone levels.
• Infections, such as meningitis.
• Problems with memory, concentration, mood or behavior.
• Problems with balance, coordination and walking.
• Stroke or bleeding in the brain.
• Problems with the eustachian tube in the ear.

Sometimes skull base tumors can spread. Noncancerous skull base tumors generally do not spread. Cancerous skull base tumors can grow into nearby tissues and spread to the lymph nodes, lungs, liver or other parts of the body. Chordomas, chondrosarcomas, sinonasal carcinomas and olfactory neuroblastomas are more likely than other types of skull base tumors to spread throughout the body.

Whether or not skull base tumors spread, and how quickly they do so, depends on the type and grade of the tumor. High-grade cancerous tumors are more aggressive. They likely will spread more quickly than low-grade tumors. The grade of a tumor shows how different the tumor cells are from healthy cells. High-grade tumors have irregular cells and tend to grow and spread very quickly.

Your doctor or other healthcare professional will ask you about your medical history and any symptoms you have. You also will have a physical exam to check your vision, hearing, balance, coordination, sensation, strength and reflexes. This can help your healthcare professional figure out which part of your brain might be affected by the tumor.

Other tests to diagnose skull base tumors may include:

• Imaging tests, such as a CT scan, MRI or PET scan. These tests take pictures of your brain and surrounding structures to show the size and location of the tumor. They also can show if there is any pressure or blockage of the cerebrospinal fluid, which is the fluid that surrounds the brain and spinal cord.
• Biopsy. In this procedure, a healthcare professional takes a small sample of the tumor and sends it to a lab to be tested. A biopsy is done by removing a small part of your skull and using a needle to take a sample of the tumor.
• Blood tests. Your healthcare professional may draw a sample of blood and test your hormone levels and other relevant labs, which may indicate the presence of certain types of tumors.
• Tests of hearing and vision. Because skull base tumors can affect hearing and vision, these tests are needed to look for problems with function and to examine the nerves to see if the tumor is compressing the nerves.

Prognosis and life expectancy with skull base tumors is dependent on many factors, such as the type of tumor, tumor grade, location of the tumor, your age and your overall health.

There are several options to treat a skull base tumor. Your healthcare team considers many factors when creating a treatment plan. These factors might include the tumor's location, how fast it's growing, whether it has spread to other parts of the brain. Other factors include the results of tests on the tumor cells, and whether the tumor is causing symptoms. Your care team also considers your age and your overall health.

The goal of treating skull base tumors is to remove the tumor or stop the growth of the tumor without causing damage to the nearby tissues.

Treatment options include:

• Surgery. Usually, surgery is the first treatment for skull base tumors. This is done to remove the skull base tumor, either partially or completely. Surgery to remove the tumor may not be the best option for skull base tumors that have more risk of complications with removal. Surgical techniques may include cutting a small section of the skull so that surgeons can access the brain to remove the tumor.

  There are less invasive surgeries, such as endoscopic surgery. This technique allows surgeons to use a thin tube with a camera through the nostrils. The surgeon uses tiny surgical tools, placed into the nostril with the tube, to remove the tumor.

  Surgeons may use advanced technologies, such as intraoperative MRI, to guide them during surgery.

• Radiation therapy. This type of therapy uses very focused, powerful beams of energy, usually X-rays, to destroy tumors. For skull base tumors, radiation therapy may be used after surgery to destroy any tumor cells not removed by surgery.

  There are several types of radiation therapy available, including stereotactic radiosurgery. This type of therapy targets skull base tumors with very high doses of energy beams directed at the tumor, sparing nearby cells and tissues from damage. Stereotactic radiosurgery is usually used on small tumors.

  Another type of radiation therapy is fractionated radiation therapy. Instead of one intense session, smaller doses of energy beams are delivered in several sessions over the course of a few weeks. Fractionated radiation therapy is usually used on larger or more complicated tumors.

  Proton therapy also may be used to treat skull base tumors. This type of radiation uses particles called protons instead of X-ray (photon) beams. Proton therapy targets the tumor more precisely. It may be used to treat tumors located near the optic nerves, brainstem or other risky areas.

• Chemotherapy. This treatment involves very strong medicines designed to kill or stop the growth of tumor cells. There are many different types of chemotherapy medicines. These may be given through a vein or by a pill that you swallow. Chemotherapy may be used after surgery or in addition to other treatments.

  Chemotherapy is less commonly used for skull base tumors unless they are cancerous and growing very quickly. It may be used in combination with other therapies for cancers such as sinonasal cancers.

• Watchful waiting. Some people may not need treatment for certain skull base tumors. These tumors may include small, noncancerous tumors that don't cause any symptoms. Instead, your healthcare professional may suggest monitoring the tumor with regular imaging tests to check for changes.

Potential future treatments

Ongoing research in cancer treatment and neurosurgery may lead to potential future treatments for skull base tumors. While current treatment methods such as surgery, radiation and chemotherapy remain the standard methods, advances in technology, drug development and precision medicine offer new possibilities for more effective and less invasive treatments.

Gene therapies and immunotherapy show potential, as well as medicines that target and destroy specific cells in the skull base tumor. Researchers also are exploring new ways to use existing techniques, including proton beam therapy and endoscopic surgery.

There are no alternative medicines that can cure skull base tumors. But some complementary and alternative treatments may help with common tumor symptoms. These may include pain, fatigue and stress.

Some alternative and complementary therapies that you may find helpful include:

• Meditation, guided imagery and other mindfulness practices.
• Yoga.
• Relaxation exercises.
• Acupuncture.
• Massage therapy.
• Physical activity.

If you're interested in alternative medicines and complementary therapies for skull base tumors, talk about it with your healthcare team. Ask about the benefits and potential risks. And discuss with your care team what options might be helpful and safe for you.

Learning that you have a skull base tumor can be overwhelming. But you can take steps to cope after your diagnosis. Take steps to:

Find out all you can about your type of skull base tumor

Write down your questions and bring them to your appointments. As your healthcare professional answers your questions, take notes. Or ask a friend or family member to come along to take notes.

The more you and your family know and understand about your care, the more confident you'll feel when it's time to make treatment decisions.

Get support

Find someone you can share your feelings and concerns with. You may have a close friend or family member who is a good listener. Or speak with a clergy member or counselor.

You may find it helpful to talk to other people who have had skull base tumors. Ask your healthcare team about support groups for people with skull base tumors. These support groups may be available online and in your area.

Take care of yourself

Choose a healthy diet that is rich in fruits, vegetables and whole grains whenever possible. Check with your healthcare professional to see if it's safe for you to exercise. Get enough sleep so that you feel rested.

Reduce stress in your life by taking time for relaxing activities, such as listening to music or writing in a journal.

If you have symptoms that worry you, make an appointment with a doctor or other healthcare professional. If you have a skull base tumor, you'll likely be referred to a specialist.

Specialists who care for people with skull base tumors include:

• Doctors who diagnose and treat brain and spinal cord conditions, called neurologists.
• Surgeons who operate on the brain and spinal cord, called neurosurgeons.
• Doctors who diagnose and treat tumors that affect the bones, called orthopedic oncologists.
• Surgeons who operate on bones and joints, called orthopedic surgeons.
• Doctors who diagnose and treat ear, nose and throat conditions and head and neck conditions, called otolaryngologists.
• Doctors who diagnose and treat conditions affecting hormones and the endocrine system, called endocrinologists.
• Doctors who diagnose and treat conditions affecting the eyes and vision, called ophthalmologists.
• Doctors who use radiation to treat cancers and tumors, called radiation oncologists.
• Doctors who use medicine to treat cancer, called medical oncologists.

Here's some information to help you get ready for your appointment.

What you can do

• Write down any symptoms you've been experiencing and how long you've had them.
• List your key medical information, including all conditions you have and the names of any medicines you're taking. Include prescription medicines and medicines you can buy without a prescription.
• Note any family history of skull base tumors, especially in a first-degree relative, such as a parent or sibling.
• Take a family member or friend along. Sometimes it can be difficult to remember all of the information provided to you during an appointment. Someone who goes with you may remember something that you missed or forgot.
• Write down questions to ask your healthcare professional.

Questions to ask at your first appointment include:

• What may be causing my symptoms?
• Are there any other possible causes?
• What kinds of tests do I need? Do these tests require any special preparation?
• What do you recommend for the next steps in determining my diagnosis and treatment?
• Should I see a specialist?

Questions to ask an oncologist or a neurologist include:

• Do I have a skull base tumor?
• What type of skull base tumor do I have?
• How will the tumor grow over time?
• What might be the consequences?
• What are the goals of my treatment?
• Am I a candidate for surgery? What are the risks?
• Am I a candidate for radiation therapy? What are the risks?
• Will I need chemotherapy?
• What treatment approach do you recommend?
• If the first treatment isn't successful, what will we try next?
• What is the outlook for my condition?
• Do I need a second opinion?

In addition to the questions that you've prepared, don't hesitate to ask any other questions that may come up during your appointment.

What to expect from your doctor

Be prepared to answer questions about your symptoms and your health history. Questions may include:

• What are your symptoms?
• When did you first notice these symptoms?
• Have your symptoms gotten worse over time?
• If you have pain, where does the pain seem to start?
• Does the pain spread to other parts of your body?
• Have you participated in any activities that might explain the pain, such as a new exercise or a long stretch of gardening?
• Have you experienced any weakness or numbness in your legs?
• Have you had any difficulty walking?
• Have you had any problems with your bladder or bowel function?
• Have you been diagnosed with any other medical conditions?
• Are you currently taking any medicines, including prescription medicines and medicines that you can get without a prescription?
• Do you have any family history of noncancerous or cancerous tumors?