Meningiomas are common primary brain tumors originating from the meninges, the protective layers surrounding the brain and spinal cord. Most grow slowly and are classified as benign. A tuberculum sellae meningioma (TSM) is a specific type defined by its precise anatomical location at the base of the skull, representing a distinct subgroup of anterior skull base tumors.
The tuberculum sellae is a small bony prominence on the sphenoid bone in the anterior skull base. TSMs arise from the dura mater in this region, including the tuberculum sellae, chiasmatic sulcus, and diaphragm sellae. These tumors are relatively uncommon, constituting 3% to 10% of all intracranial meningiomas.
Understanding the Location and Symptoms
The tuberculum sellae location is significant due to its immediate proximity to several delicate structures. The tumor sits directly beneath the optic chiasm, where the optic nerves cross. As the TSM grows, it pushes the optic chiasm superiorly and posteriorly, leading to the primary and most frequent symptom: progressive vision loss.
Vision impairment often begins subtly in one eye but typically progresses to involve both eyes. Compression of the optic pathway classically causes bitemporal hemianopsia, a visual field defect where the outer half of the visual field is lost in both eyes, often asymmetrically. TSMs can also extend into the optic canal, directly compressing the optic nerve and causing profound or acute vision changes.
Headaches are a common secondary complaint. If the tumor extends downward into the sella turcica, it may compress the pituitary gland. This can lead to hormonal imbalances or endocrine dysfunction, manifesting as changes in metabolism or reproductive function. The tumor can also contact major blood vessels, such as the internal carotid arteries, though symptoms from vascular compression are less common.
Confirming the Diagnosis
Diagnosis focuses on precisely locating the tumor and assessing its relationship to surrounding neurovascular structures. Magnetic Resonance Imaging (MRI) with a contrast agent is the standard imaging modality. The tumor typically appears as a well-defined mass that enhances vividly and uniformly after the contrast dye is administered.
MRI provides detailed images of the tumor’s size and displacement of the optic nerves and chiasm. Contrast helps identify the characteristic “dural tail sign,” an enhancement of the meninges near the tumor, supporting the meningioma diagnosis. Computerized Tomography (CT) scans offer complementary information for evaluating bony structures, such as assessing bone thickening (hyperostosis) at the tuberculum sellae or invasion into the optic canal.
A comprehensive ophthalmological evaluation is necessary for diagnosis and treatment planning. This includes detailed visual acuity testing, fundoscopy, and formal visual field testing. These tests objectively document the extent of vision loss, helping determine the pressure on optic structures and serving as a baseline for monitoring treatment effectiveness.
Management and Treatment Options
Management is tailored based on tumor size, symptom severity, and the patient’s overall health. For small, asymptomatic tumors or for elderly patients, “watchful waiting” may be appropriate. This involves regular follow-up MRI scans, typically every six to twelve months, to monitor for tumor growth or new symptoms.
Surgical resection is the primary treatment for TSMs causing progressive vision loss or significant growth. The objective is maximum safe removal while preserving or improving neurological function, especially vision. The tumor’s location near the optic nerves, carotid arteries, and hypothalamus makes this a challenging procedure requiring specialized neurosurgical expertise.
Two main surgical approaches are commonly used: the transcranial approach (TCA) and the endoscopic endonasal approach (EEA).
Transcranial Approach (TCA)
The TCA involves opening the skull (craniotomy) to access the tumor from above, often using pterional or subfrontal routes.
Endoscopic Endonasal Approach (EEA)
The EEA is a minimally invasive technique accessing the tumor through the nasal cavity and sphenoid sinus. This offers a direct path and potentially better outcomes for vision stabilization in smaller, midline tumors.
Radiation therapy is an important option, used either primarily or as an adjunct following surgery.
Stereotactic Radiosurgery (SRS)
SRS, such as Gamma Knife, delivers a highly focused, high dose of radiation in a single session to destroy tumor cells. It is often used for smaller tumors, residual tumor remaining after surgical removal, or for patients who are not surgical candidates.
Fractionated Radiotherapy (RT)
RT delivers the radiation dose in smaller amounts over several weeks. This may be preferred for larger tumors or those located close to the optic apparatus, where protecting the optic nerves from high-dose exposure is necessary. Radiation therapy aims to halt tumor growth and reduce recurrence.
Long-Term Outlook and Follow-Up Care
The long-term outlook for most individuals with a TSM is generally favorable because the majority are classified as World Health Organization (WHO) Grade I, meaning they are slow-growing and benign. Visual outcome is a major factor in the prognosis; timely intervention often leads to stabilization or improvement of vision. Shorter symptom duration before treatment generally leads to a better prognosis and degree of visual recovery.
Ongoing monitoring is necessary after treatment to watch for tumor recurrence. Patients undergo regular follow-up MRI scans, typically scheduled yearly, even after complete tumor removal. Recurrence rates are lowest following a complete tumor resection (Simpson Grade I or II removal).
Continued ophthalmological assessments are important to monitor visual function and detect changes. If the tumor involved the pituitary gland, periodic endocrine testing may be required to monitor for long-term hormonal deficiencies. Consistent surveillance ensures that any regrowth is detected early, allowing for prompt re-treatment.