Skull Base Tumor

A skull base tumor is a growth that forms in the area behind the eyes and nose, beneath the brain. This part of the skull is where many important nerves and blood vessels pass, and it separates the brain from the neck.

Skull base tumors can be benign (noncancerous) or malignant (cancerous), and they can form inside or outside the skull. Even noncancerous tumors can be serious, because they may press on the brain, nerves or blood vessels nearby. These tumors are rare.

Types & Stages

Doctors describe skull base tumors by whether they are benign or malignant, where they start and how they affect nearby structures. Some tumors begin elsewhere in the body and grow into the skull base.

Common benign types include:

• Acoustic neuroma (also called vestibular schwannoma)
• Meningioma
• Pituitary tumor
• Paraganglioma
• Osteoma

Common malignant types include:

• Chordoma
• Chondrosarcoma
• Carcinomas, such as adenoid cystic carcinoma, nasopharyngeal carcinoma, squamous cell carcinoma and adenocarcinoma
• Olfactory neuroblastoma (also called esthesioneuroblastoma)

Skull base tumors are not described with a single simple number. Instead, doctors look at:

• The type of tumor
• Its size and location
• How quickly it is growing
• Whether it has spread into nearby tissue or other areas

This helps your care team plan the best treatment.

Signs & Symptoms

Symptoms depend on the size, type, and location of the tumor. Some skull base tumors cause no symptoms at all and are found by chance during imaging done for another reason.

Visit a doctor if you are experiencing any of these symptoms:

• Headaches
• Neck pain
• Vision changes, such as blurry, double or lost vision
• Hearing loss or ringing in the ears
• Problems with balance or coordination
• A hoarse voice
• Trouble breathing or swallowing
• Changes in your sense of smell
• Nosebleeds

Many of these symptoms can be caused by conditions that are not a tumor. Still, if a symptom is new, lasting, or worries you, talk with a healthcare provider.

Diagnosis

Tests and procedures used to diagnose a skull base tumor may include:

• Physical and neurological exam. Your doctor reviews your symptoms and health history, and checks your vision, hearing, balance, coordination, reflexes and memory.
   
• Imaging tests. A CT scan, MRI or PET scan can show the size and location of the tumor and how it affects nearby structures.
   
• Biopsy. A small sample of tissue is removed and examined under a microscope when needed. In selected cases, this may be done during a nasal endoscopy or with an image-guided needle when the tumor is hard to reach.
   
• Blood tests. These may check hormone levels, which can point to certain types of tumors.
   
• Hearing and vision tests. These check how well these senses are working and whether the tumor is pressing on nearby nerves.

Treatment

Treatment depends on the type of tumor, its location, how fast it is growing, your symptoms and your overall health. The goal is to remove the tumor or stop its growth while protecting nearby tissue. Your care team can help explain the benefits and risks of each option.

Treatment may include:

• Surgery. This is often the first treatment. Some tumors are removed with open surgery, while others can be reached through minimally invasive endoscopic surgery, using a thin tube with a camera passed through the nose.
   
• Radiation therapy. Radiation uses focused, high-energy beams to destroy tumor cells, often after surgery. Options include stereotactic radiosurgery, which delivers a precise dose to small tumors, and fractionated radiation, which spreads smaller doses over several sessions for larger or more complex tumors. Proton therapy may be used in select cases, especially for tumors near critical areas such as the optic nerves or brainstem.
   
• Watchful waiting. Some small, slow-growing, noncancerous tumors that are not causing symptoms may simply be monitored over time with regular imaging.

Clinical trials may also be an option. These studies test new treatments or new ways to use current ones.

Ask your care team whether a clinical trial may be right for you.

Causes & Risk Factors

Because skull base tumors are rare, their causes are not well understood. Some factors may raise the risk, including:

• Inherited genetic conditions. Certain genetic conditions are linked to these tumors, such as neurofibromatosis type 2, multiple endocrine neoplasia type 1 (MEN1) and familial isolated pituitary adenoma (FIPA).
   
• Family history. A family history of related tumors or hereditary cancer syndromes may increase risk.
   
• Prior radiation exposure. Past radiation, especially to the head and neck, may play a role.
   
• Certain chemical exposures. Long-term contact with some substances may raise risk, such as wood dust, formaldehyde, asbestos, vinyl chloride, arsenic and herbicides. There may also be a possible link to radon or heavy air pollution.
   
• Prior tumors. A past tumor, especially in the head or neck, may increase the risk of a later skull base tumor.
   
• Smoking and alcohol use. These are linked to a higher risk of certain related cancers, such as those in the sinuses or nasopharynx (the upper part of the throat behind the nose).

Having a risk factor does not mean you will develop a skull base tumor, and many people with one have no clear risk factors. Talk with your healthcare provider about your personal risk.

Screening

There is no routine or simple screening test to find skull base tumors early.

Because there is no screening test, it is important to pay attention to your body and report symptoms that do not go away, such as ongoing headaches, vision or hearing changes, or balance problems.

If you have symptoms that are new, lasting, or unusual for you, talk with a healthcare provider about whether further evaluation is needed.

This information is for general education only and is not a substitute for medical advice. Please consult a qualified healthcare provider for diagnosis, treatment recommendations, and guidance based on your personal health history.