Brain tumors come in many types. From gliomas to adenomas, it can be overwhelming to know what each term means for a diagnosis. Skull base tumors are a category of primary brain tumors that form at the base of the skull.
Centers for Neurosurgery, Spine & Orthopedics (CNSO) is New Jersey’s most comprehensive brain and spine center. Here, the CNSO medical team discusses what skull base tumors are, their symptoms, and how they can be treated.
Quick Facts About Skull Base Tumors
- Skull base tumors are tumors that form in and around the foundation or base of the skull.
- Symptoms develop due to pressure on the brain or cranial nerves. The most common symptoms include headaches, double vision, blurred or loss of vision, dizziness or loss of balance, swallowing difficulties, altered sense of smell, hearing loss, and tinnitus. Although these are the most common symptoms caused by skull base tumors, they can cause almost any neurological symptom.
- Treatment options include surgery, radiation therapy, and observation.
- CNSO offers cutting-edge brain tumor treatment at locations across New Jersey.
What Is a Skull Base Tumor?
Generally, tumors arise from DNA changes within cells or tissues that cause abnormal growth, leading to the formation of a mass. Physicians are not always sure what causes this DNA change. In some patients, it may be due to an inherited mutation. In others, there is no clear cause.
Skull base tumors are masses of abnormal cells and tissue that form in and around the skull base. The skull base is an intricate structure featuring five interlocking bones. The skull base is the bony foundation of the skull, which supports the brain and separates it from the extracranial structures, such as the eyes and nasal cavity. The cranial nerves, which provide vision, movement of the eyes, swallowing, movement of the face, hearing, and balance, pass through the skull base, as do all the blood vessels that provide the critical blood supply to the brain. Due to the complex anatomy of the skull base and the critical structures of the brain stem, cranial nerves, and cerebral blood vessels that it surrounds and supports, treating tumors here is challenging and often requires a multidisciplinary approach.
Types of tumors are differentiated by the tissue from which they form. Common ones include:
- Meningioma: This is a common type of brain tumor. The vast majority of brain meningiomas are benign and may not cause any symptoms until they are large enough to put pressure on and affect the surrounding structures, including the brain, brain stem, and cranial nerves.
- Vestibular schwannoma (also known as acoustic neuroma): These originate in the brainstem and then grow into the inner ear, known as the internal auditory canal. They interfere with the ability to hear, affect balance, and control facial muscles, and can become life-threatening by putting pressure on the brain and brainstem if allowed to grow.
- Epidermoid/dermoid cysts: These are congenital, slow-growing cysts that can occur at the skull base. They are benign growths that cause symptoms by mass effect, or pressure on the brain and cranial nerves. Rarely, these cysts rupture, causing severe headaches and a condition called chemical meningitis.
- Chordoma: Chordoma is a rare bone tumor. They are cancerous but slow-growing, and surgical removal of the tumor is the first-line treatment. These types of tumors almost always require postoperative radiation treatment, and proton beam therapy has been shown to be very effective against chordomas.
- Craniopharyngioma: These tumors grow slowly and are usually benign. They form near the pituitary gland, often in the pituitary stalk (the connection between the pituitary gland and the brain). As they grow, they can put pressure on the optic nerves and chiasm, causing visual loss, as well as damage the pituitary or pituitary stalk, causing hormone deficiencies.
- Pituitary adenoma: Pituitary adenomas are commonly occurring benign tumors of the pituitary gland. Large tumors can cause pressure on the optic nerves and chiasm, leading to vision loss, as well as pressure on the pituitary, causing loss of hormone function. Symptoms often include headaches, loss of energy level, weight gain, galactorrhea or leaking of milk from the breast, amenorrhea, loss of libido, and acromegaly (coarsening of facial features and growth of the hands and feet). While pituitary adenomas are not cancerous, they can cause serious symptoms and side effects.
- Paraganglioma: A paraganglioma is a rare tumor that usually forms along major blood vessels and nerve pathways in the neck and head. The tumor is typically benign, but it can be malignant. Symptoms often develop subtly over time and typically begin with loss of lower cranial nerve function, including difficulties with swallowing, as well as the development of a hoarse voice.
Symptoms and Warning Signs of a Skull Base Tumor
Small skull base tumors often do not cause noticeable warning signs. Symptoms develop as the tumor grows large enough to put pressure on the cranial nerves or brain structures. The exact nature of the symptoms depends on which structures are impeded, though they commonly include:
- Headaches
- Nausea and vomiting
- Blurred or double vision
- Loss of Vision
- Hearing loss
- Tinnitus
- An altered sense of smell
- Difficulty swallowing
- Balance problems
- Loss of hormone function, including decreased energy level, weight gain, and changes in the skin
Skull base tumor symptoms get worse over time as the tumor continues to grow. If a patient notices new symptoms developing, it is important that they seek prompt medical attention. Treatment is the only way to prevent serious complications, including permanent neurological deficits.
Diagnostic Testing for Skull Base Tumors
To plan an effective treatment, physicians must first diagnose the tumor. The diagnosis process begins with a thorough medical evaluation and neurological exam to determine how the tumor is impacting brain function. These tests are followed by a magnetic resonance imaging (MRI) scan to locate the tumor within the brain and often a specialized computed tomography (CT) scan to more closely look at the bony anatomy and arteries at the base of the brain. Depending on where the tumor is located or what type of tumor is suspected, further testing may be ordered, including a thorough ophthalmological evaluation with visual fields, endocrinological evaluation, and hearing test.
Treatment Approaches for Skull Base Tumors
Following diagnosis, the neurosurgeon and the patient will discuss their treatment options. The best approach depends on the tumor’s size, type, and rate of growth. Treatment options include:
- Surgery: Brain tumor surgery, aiming to remove the whole tumor if possible, is the best treatment option if it can be done safely without serious neurological injury. Often, a patient’s neurological symptoms will improve following surgery due to relieving the pressure off the cranial nerves, brain, and brainstem.
- Radiation therapy: This treatment targets tumors with focused beams of radiation to kill tumor cells. It does not relieve symptoms, since the tumor is not removed, nor does it shrink the mass, but it does prevent tumor growth.
- Observation: Very small tumors may not require direct treatment. Instead, neurosurgeons monitor their growth with frequent MRI scans.
The patient’s care team will make sure the patient understands what to expect from their diagnosis and treatment, helping the patient feel confident about their care.
Find Skull Base Tumor Treatment Near You in New Jersey
A brain tumor diagnosis can be frightening. Fortunately, compassionate care is available at Centers for Neurosurgery, Spine & Orthopedics. Led by an award-winning multidisciplinary team, CNSO offers comprehensive brain tumor care at convenient locations near you across New Jersey. CNSO’s conservative treatment philosophy prioritizes non-invasive methods to give patients greater peace of mind. Contact CNSO to learn more about what skull base tumors are and how they can be treated.
FAQ About Skull Base Tumors
Are skull base tumors always cancerous?
Rarely are skull base tumors cancerous. The three most common skull base tumors, meningiomas, vestibular schwannomas, and pituitary adenomas, are almost always benign.
What are benign vs. malignant tumors?
Benign brain tumors remain localized to their point of origin and do not spread. Malignant or cancerous brain tumors are aggressive, grow rapidly, and invade surrounding tissues, including the brain, cranial nerves, and skull base.
How serious are skull base tumors?
All brain tumors are serious due to their location near the brain, but some types are more dangerous than others. Skull base tumors occur near the brainstem and cranial nerves, which are critical but delicate structures of the brain, making them dangerous and challenging to treat. The level of concern for skull base tumors depends on whether a patient has developed symptoms and the tumor’s type, size, and rate of growth.
Can skull base tumors be removed without surgery?
Surgery is the only way to completely remove a skull base tumor. Not all tumors need to be removed, however. Some small tumors can be treated non-invasively or monitored for growth and only treated if they grow, start to cause changes or swelling in the brain, or if symptoms develop.
