Diagnosis
Diagnosing a brain, spine, or skull base tumor may involve one or more of the following:
Neurological Exam
A neurological exam assesses the brain and the major nerves that relay information to and from the brain. This exam can include the following tests:
- Eye movement test. The patient follows an object with their eyes.
- Pupil reaction test. A light is flashed into the patient’s eye to see how the pupil reacts to the light.
- Optic nerve test. The physician looks into the eye with a special tool to asses if the nerve is swollen due to pressure on the brain.
- Reflex test. The physician taps reflex points on the body such as the knee, wrist, and elbow.
- Balance and coordination test. The patient walks on his or her heels and toes.
- Facial muscles test. The patient smiles and grimaces.
- Tongue movement test. The patient sticks out his or her tongue.
- Mental status test. The patient answers questions that address judgment.
- Abstract thinking test. The patient answers questions that address reasoning.
- Memory test. The patient answers questions that require accessing short- and long-term memory.
- Motor strength test. Strength in major muscle groups is tested to determine any muscular weakness.
- Sensory testing. The patient’s skin sensation is tested using light touch, pinpricks, and warm or cold objects to determine any deficits.
These non-invasive tests provide the physician with helpful information. Your doctor will explain what your results mean and any steps to further diagnose what’s causing the symptoms. Abnormal results do not necessarily mean a person has a brain tumor; other diseases can lead to abnormal neurological exam results. For this reason, your doctor may recommend lab work and/or medical imaging.
Medical Imaging
Medical imaging such as magnetic resonance imaging (MRI) and computerized tomography (CT) are used to produce an electronic image of the brain, spinal fluid, and bones. These images are then viewed by a neuroradiologist, who has special training to distinguish normal structures from abnormal structures.
These images help the physician determine if signs and symptoms from the neurological exam are the result of a tumor or lesion in the brain. They also help rule out any other neurological disease that could be causing the symptoms. Images can locate the tumor, show involved structures, determine tumor size, and help lead to a diagnosis of the tumor type.
A special MRI called a magnetic resonance spectroscopy (MRS) may also be used to evaluate the chemical composition of normal brain tissue and compare it to abnormal brain tissue.
Laboratory Test
A lumbar puncture (spinal tap) is a procedure that involves collecting cerebrospinal fluid (CSF).
Once a sample is collected, it is sent to the lab to test it for any infection, tumor cells, or protein, and to see if any blood is present. This information is helpful to diagnose particular types of cancers.
Blood and/or urine tests may be done to examine if the tumor is impacting or involving the endocrine system of the brain (the pituitary and hypothalamus, specifically).
Biopsy
A biopsy is a surgical procedure that removes a small amount of the tumor for inspection by a pathologist, a physician who specializes in identifying cells within tissue. The pathologist will determine the exact type of tumor. Biopsies are also conducted as a part of a surgery when attempting to remove the tumor.
There are two types of biopsies:
- Open biopsy. During this procedure, surgery is performed to expose the tumor and remove a tissue sample.
- Stereotactic needle biopsy. During this procedure, a small incision is made into the skin and a hole is drilled into the skull. A needle is then maneuvered into the tumor under computer guidance and a small amount of the tumor is aspirated into the needle. This procedure provides a safer approach to difficult biopsies or tumors that are deep in the brain or located in or around critical areas.
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