Overview of meningioma
Tuberculum sellae menigioma accounts for 7% to 10% of meningiomas, often accompanied by saddle node osteophytes. 50% are supplied by the ophthalmic and sieve arteries, 20% by the middle meningeal artery, and 16% by the anterior cerebral artery.
Etiology
The cause of saddle node meningioma is still unknown. It is thought to be related to internal environmental changes and genetic variations, but not due to a single factor. Craniocerebral trauma, radioactive irradiation, viral infection, etc. make cell chromosome mutation or cell division speed increase may be related to the occurrence of meningioma. In recent years, molecular biology studies have confirmed that meningiomas are most commonly caused by the absence of a gene fragment on 22 pairs of chromosomes.
Symptoms
1. Decreased visual acuity in one or both eyes and bilateral temporal hemianopsia, optic nerve atrophy.
2. Often without papillary edema, olfactory and psychiatric disorders (differentiated from olfactory groove meningioma).
3. Endocrine disorders may be present, but the pterygoid saddle is not enlarged (differentiated from pituitary tumor).
4. Larger tumors may have headache, epilepsy, mental changes, fundus papillae edema and other manifestations.
Examination
1. Head CT examination
The manifestation is a homogeneous slightly high-density or isodense mass next to the saddle, with clear boundaries, connected to the dura mater and/or the inner plate of the skull with a broad base, and there may be localized cranial bone hyperplasia.
2. Head CTA (CT angiography) examination
CTA (CT angiography) of the head can clarify the tumor hematoma and its relationship with bilateral internal carotid arteries, middle cerebral arteries and anterior cerebral arteries.
3. MRI (magnetic resonance imaging) of the head
T1WI is equal signal or slightly low signal, T2WI is high signal or equal signal, and enhancement scan usually shows obvious homogeneous enhancement of suprasellar lesions, encircling one or both internal carotid arteries and middle cerebral arteries, and the tumor adheres to the pterygoid plateau, optic intersection sulcus and the saddle node dura, which can be seen in the characteristic rat’s tail sign or dura caudalis sign.
4. Head DSA (digital subtraction angiography) examination
Anteroposterior view shows the typical sunburst sign; the blood supply artery is mostly from the posterior scleral artery of the ophthalmic artery branch; the internal carotid artery and anterior cerebral artery are often seen to be compressed and displaced.
Diagnosis
The possibility of this disease should be considered in anyone with the typical presentations described above, or in those with chronic headaches, adult epilepsy, psychiatric changes, and fundus optic papillae edema.
Differential diagnosis
1. Olfactory sulcus meningioma
Mainly psychiatric symptoms, often with euphoria, inattention, unilateral or bilateral loss of sense of smell, and about 30% of them have grand mal seizures. lesions on MRI are usually large in size, and mainly in the olfactory sulcus region.
2. Pituitary tumor
Pituitary tumor is often combined with endocrine manifestations, and the visual field disorder is mostly bilateral temporal hemianopsia. CT and MRI show that the pterygoid saddle is enlarged, and the lesion is located in the saddle or develops from the saddle to the saddle, and the normal pituitary gland is compressed and displaced.
Treatment
1. Surgical resection is the main treatment strategy, with unilateral frontal or pterygoid approach for small size, and coronal incision in the hairline and bilateral bone flap resection for large size.
2. Three steps of microsurgery: ① electrocoagulation of blood vessels supplying blood to the tumor from the dura to separate it from the dura; ② resection and decompression of the tumor from the center of the tumor; ③ separation of the tumor from the periphery along the arachnoid space.
3. Intraoperative attention should be paid to the encapsulation, compression and displacement of important blood vessels at the base of the skull.
4. Postoperative residual or recurrent patients can be treated with radiotherapy, and stereotactic radiosurgery is preferred.