Skull base chordoma is a rare cancer originating from notochord remnants, embryonic tissues that typically disappear after birth. This slow-growing tumor forms in the bones at the base of the skull, a complex area near the brainstem and nerves. As it expands, the tumor can press on surrounding structures, causing significant issues.
Understanding Skull Base Chordoma
Skull base chordoma arises from vestigial notochordal cells, tissues left over from embryonic development. These cells, which normally disappear after birth, can sometimes form a tumor in adulthood. The clivus, a bone at the center of the skull base behind the nose and eyes, is the most common site for these tumors.
Chordomas can occur at any age, but they most frequently affect adults between 40 and 60 years old. There is a slight male predominance, with males diagnosed slightly more often than females.
Recognizing the Signs
Symptoms of a skull base chordoma often develop gradually as the tumor expands and presses on nearby neurological structures. Headaches are a common early symptom, often localized to the back of the head or behind the eyes. Vision problems, such as double vision (diplopia), can also occur due to pressure on cranial nerves controlling eye movement.
Facial numbness or weakness may develop if the tumor affects the trigeminal or facial nerves. Some individuals may experience changes in voice quality, difficulty swallowing, or hoarseness due to involvement of the lower cranial nerves. These symptoms are often non-specific, leading to a delay in diagnosis.
Diagnosis and Evaluation
Diagnosis of a skull base chordoma typically begins with a thorough neurological examination to assess cranial nerve function, reflexes, and coordination. Imaging studies are then performed to visualize the tumor and determine its exact location and extent. Magnetic Resonance Imaging (MRI) is the primary imaging modality, providing detailed soft tissue views that highlight the tumor’s characteristic features and its relationship to surrounding brain structures.
Computed Tomography (CT) scans are also employed, offering superior bone detail to show the tumor’s destructive effects on the skull base. These scans help in planning surgical approaches by mapping the bony anatomy. A definitive diagnosis requires a biopsy, where a small tissue sample is obtained from the tumor, often through a minimally invasive approach, and then examined under a microscope by a neuropathologist.
Treatment Approaches
Treatment for skull base chordoma is complex and typically involves a multidisciplinary team of neurosurgeons, radiation oncologists, and other specialists. The primary goal is to remove as much of the tumor as safely possible. Surgical removal is challenging due to the tumor’s deep location at the skull base and its proximity to delicate structures like the brainstem, cranial nerves, and major blood vessels.
Neurosurgeons often use specialized techniques, such as endoscopic endonasal approaches, to access the tumor through the nasal passages, minimizing disruption to surrounding tissues. Despite maximal safe resection, complete removal is often not achievable due to the tumor’s infiltrative nature and location. Therefore, surgery is frequently followed by radiation therapy to target any remaining microscopic tumor cells.
Proton beam therapy is a highly effective form of radiation therapy for skull base chordomas. This advanced technique delivers a precise dose of radiation to the tumor while minimizing exposure to surrounding healthy brain tissue, reducing the risk of side effects. This precision is beneficial given the sensitive location of these tumors. The combination of surgery and targeted radiation aims to achieve long-term local control of the disease, preventing recurrence and improving patient outcomes.
Living with Chordoma and Outlook
After initial treatment, individuals with skull base chordoma require regular, long-term follow-up with imaging studies, typically MRI scans, to monitor for tumor recurrence. These appointments are usually scheduled every 6 to 12 months in the initial years, then less frequently if the tumor remains stable. Recurrences can happen many years after initial treatment.
Patients may experience various challenges following treatment, including potential side effects from surgery or radiation, such as fatigue, neurological deficits, or hormonal imbalances. Rehabilitation services, including physical therapy, occupational therapy, and speech therapy, can be beneficial in managing these effects and improving quality of life. The outlook for skull base chordoma varies significantly among individuals, depending on factors such as the extent of tumor removal, the tumor’s response to radiation, and the presence of any genetic mutations within the tumor.