Sphenoid wing meningioma (SWM) is a slow-growing tumor arising from the outer arachnoid meningothelial cells, originating from the sphenoid ridge (lesser and greater wings). It is the most common tumor extending from the intracranial cavity into the orbit, accounting for 11–20% of all intracranial meningiomas. Meningiomas are the most frequent intracranial tumors, comprising more than one-third of primary brain tumors 1), with an annual incidence of symptomatic meningioma of approximately 2 per 100,000 population.
Morphologically, it is broadly classified into two types: globoid and en plaque. The globoid type is further divided into three groups based on location.
| Classification | Synonym | Characteristics |
|---|---|---|
| Medial type | Clinoidal type | Approximately half of all cases. Visual impairment due to optic canal invasion. |
| Intermediate type | Alar type | Chronic progressive proptosis. Easily misdiagnosed as thyroid eye disease. |
| Lateral type | Pterional type | Asymptomatic until large. Discovered due to increased intracranial pressure. |
The medial type involves the anterior visual pathway, intracranial arteries, and cavernous sinus, resulting in higher morbidity, mortality, and recurrence rates than other types. The average age of onset is 50 years, with about 80% of cases in women, and peaks in the 20s and 50s.
The en plaque type is a form in which the tumor spreads widely and thinly along the sphenoid ridge, often accompanied by hyperostosis. Unlike the globular type, the borders are unclear, making complete resection difficult in many cases.
Symptoms vary depending on the location and direction of tumor extension.
The intermediate type is characterized by chronic progressive proptosis as the main symptom, and even in the absence of thyroid dysfunction, its clinical findings are similar to those of thyroid eye disease. Imaging studies (CT/MRI) to confirm bone thickening or mass are essential for differentiation.
Sphenoid wing meningioma arises from the outer arachnoid meningothelial cells, but definitive environmental risk factors are not clear.
The diagnosis of sphenoid wing meningioma is evaluated using a combination of CT and MRI.
| Examination | Main Findings |
|---|---|
| CT | Iso- to slightly hyperdense, homogeneous strong enhancement after contrast, bone thickening/calcification |
| MRI | T1/T2 etc. ~ mildly high signal, post-Gd enhancement, dural tail |
68Ga-DOTATATE PET/CT can differentiate meningiomas from vascular lesions based on the presence or absence of somatostatin receptor expression. Cavernous sinus venous malformations, which do not express somatostatin receptors, are PET-negative, providing important information for determining the indication for radiosurgery without tissue diagnosis 3).
Treatment options include observation, surgery, radiation therapy, and chemotherapy, and the choice is based on tumor size, location, symptoms, WHO grade, and the patient’s general condition.
This is an appropriate option for asymptomatic elderly patients or those with multiple medical problems.
The mainstay of treatment is surgical tumor removal. In cases with optic canal invasion, visual function recovery is often difficult. The gross total resection rate is approximately 50%, and the postoperative complication rate ranges from 1% to 18%. The 5-year recurrence-free survival rate for WHO grade I is 88%.
Although no consensus on bone reconstruction has been reached, it is sometimes performed to prevent pulsatile enophthalmos, meningocele formation, and temporal muscle atrophy. Reconstruction materials include titanium mesh, inner table cranial bone graft, and polymethyl methacrylate (PMMA).
Radiation is administered after tumor resection, and surgery is repeated for regrowth. Stereotactic radiosurgery and stereotactic radiotherapy are also being attempted.
Many drugs including mifepristone have been tried, but tumor regression is minimal or absent despite significant systemic toxicity. Combination therapy with hydroxyurea is under evaluation.
Adjuvant radiotherapy after subtotal resection is effective, with local control rates of 92–100% for stereotactic radiosurgery and fractionated stereotactic radiotherapy. The 5-year progression-free survival after subtotal resection of benign meningioma is reported to be 89%1), and combining adjuvant radiotherapy for incomplete resection is a standard treatment strategy.
The origin is outer arachnoid meningeal epithelial cells. Pathological features include the following:
Grade I (Benign)
Frequency: Approximately 90% of all meningiomas.
Pathology: Does not invade brain parenchyma even with bone invasion. Includes subtypes such as secretory, microcystic, clear cell, and lymphoplasmacyte-rich.
Recurrence rate: 7–10% at 5 years, 22% at 10 years (after total resection).
Grade II (Atypical)
Pathology: Characterized by frequent mitoses and increased nuclear/cytoplasmic ratio.
Clinical significance: Higher recurrence and malignant transformation risk than Grade I.
Grade III (Anaplastic)
Pathology: High mitotic activity (≥20/10 HPF), necrosis, brain parenchyma invasion. Elevated Ki-67. Grossly gray-red with malignant cell morphology1).
Prognosis: Survival <2 years without adjuvant therapy; median 5 years with adjuvant therapy1).
In a large retrospective study of 1663 cases, 90% were WHO Grade I and 10% were Grade II/III; non-skull base location, age ≥65, and male sex were reported as risk factors for higher WHO grade.
Extends from the sphenoid ridge into the orbit via the superior and inferior orbital fissures. Ocular symptoms appear due to invasion of the optic canal and cavernous sinus. Extracranial extension may involve the orbit, infratemporal fossa, pterygopalatine fossa, and paranasal sinuses, with extension through the foramen ovale and pterygopalatine canal also reported2).
Meningiomas often show positivity for progesterone receptor, epithelial membrane antigen (EMA), and somatostatin receptor 2a (cytoplasmic expression). TERT promoter mutations and CDKN2A/B deletions are defining mutations for Grade 3, and loss of H3K27me3 is associated with poor prognosis1).
Molecular imaging targeting somatostatin receptor type 2 enables differentiation between meningioma and vascular lesions, which is difficult with conventional morphological imaging.
Ofori-Darko and McClelland (2025) reported a case of a 27-year-old man with suspected sphenoid wing meningioma on MRI, in which 68Ga-DOTATATE PET/CT confirmed negative somatostatin receptor expression, leading to a revised diagnosis of cavernous sinus venous varix and avoidance of stereotactic radiosurgery3). This highlights the importance of assessing radiotherapy indications without tissue diagnosis.
Currently, applications are being developed to differentiate postoperative changes and improve the accuracy of radiotherapy target delineation3).
As an alternative to conventional craniotomy, the endoscopic transorbital approach is gaining attention as a minimally invasive surgery for sphenoid wing and spheno-orbital meningiomas. It has been reported to be effective even in cases with hyperostosis6).
Foulsham et al. (2022) reported a case of multilayered macular hemorrhage (resembling Terson syndrome) after resection of a sphenoid wing meningioma via the transorbital endoscopic approach, indicating that postoperative visual complications require attention even in minimally invasive surgery6).
The following targeted therapies are being investigated for recurrent and high-grade meningiomas.
In vitro studies targeting angiogenesis via platelet-derived growth factor (PDGF), VEGF, epidermal growth factor (EGF), and the MAPK pathway have shown promising results. Anti-angiogenic agents, multikinase inhibitors, and somatostatin receptor-targeted therapies are used to stabilize progressive and high-grade meningiomas, but responses are inconsistent4).
Grigorean et al. (2026) reported a 70-year-old woman who presented with neurocognitive impairment resembling behavioral variant frontotemporal dementia due to a giant right sphenoid wing meningioma 4). After Simpson Grade I resection, frontal lobe function recovered, and the concept of reversible frontal network dysfunction caused by the combined effects of tumor mass, vasogenic edema, and white matter tract compression has been proposed.
