Tentorial meningioma

J.Sales-Llopis

Neurosurgery Service, Alicante University General Hospital, Alicante Institute for Health and Biomedical Research (ISABIAL - FISABIO Foundation), Alicante, Spain.

Tentorial meningiomas have been discussed in many articles devoted to posterior fossa meningiomas.

Cushing and Eisenhardt (1938) described 15 cases, Campbell and Whitfield (1948) five cases, Russell and Bucy (1953) reviewed 46 cases from the literature and described two of their own, Castellano and Ruggiero (1953) presented 21 cases of tentorial meningioma, Markham, Fagcr, Horrax, and Poppen (1955) described seven cases, and Tristan and Hodes (1958) eight cases.

These tumours are notorious for their ability to escape recognition clinically, a fact noted by many of the authors above ¹⁾.

Meningioma of the tentorium represent about 5% of all intracranial meningiomas reported in the literature ²⁾

Approximately 70% - 80% of cases in women ³⁾.

Tentorial meningioma classification.

Signs and symptoms of cranial hypertension are the most common findings, followed by cerebellar ataxia, psychiatric disturbances and cranial nerve dysfunction ⁴⁾.

In 1962 Barrows and Harter reviewed a large series of cases of tentorial meningiomas. They divided the patients into three groups, of which the third presented with “ataxic, slow stiff gait”, slow mentation and urinary incontinence. The ventricles were dilated in all patients ⁵⁾.

In all patients with tentorial meningiomas, a contrast-enhanced CT scan and a magnetic resonance (MRI) of the brain should be ordered. The CT scan in axial and coronal views should be carefully evaluated to see the relations of the lesion with the falx and tentorium. The CT images still provide superior bone detail and are invaluable where tumors invade bones ⁶⁾.

The MRI is more precise on revealing information about tumor localization, extension and its relations. Special attention should be given to where the tumor expands mostly into the two compartments. In fact with, MR and MR angiography (MRA) the size, dominance and collateralization of the transverse sinuses can be recognized. This factor is essential for this kind of approach. We should obtain all possible possible about the transverse sinus status. If infiltration is present, it should be quantified ⁷⁾.

Is sometimes necessary to obtain additional information about the arterial and venous system. Using the four-vessels angiography we are able to delineate the vascularity of the lesion and its relationship to the various arteries and veins in this area. The circulation supplying the tumor is carefully analyzed in order to plan both endovascular and surgical procedures. The vein of Galen, the internal cerebral veins and the basal vein of Rosenthal should be studied. As well as the superficial venous system, with the patency of the straight sinus, and the collateralization and enlargement of the normally present sinus should also be analyzed.

If the preoperative embolization is effective the surgical procedure become easier ⁸⁾.

For Cerebral CT venography see Cerebral CT venography in surgical planning for a tentorial meningioma ⁹⁾.

A 72-year-old male presented with a primary hemangioblastoma of the posterior fossa with unusual dural attachment and meningeal arterial blood supply from the external carotid artery and marginal tentorial artery. Preoperative embolization facilitated complete resection of the tumor with no resultant neurological deficit. Hemangioblastoma must be included in the differential diagnosis of tumors with dural involvement. Preoperative embolization is very useful in such tumors ¹⁰⁾.

see Tentorial meningioma treatment.

They tend to enclose, displace, or compress the adjacent cranial nerves and vascular structures. Due to their vicinity to crucial neural and vascular structures, they are a surgical challenge.

The first historic attempts at tentorial meningioma removal resulted in high rates of mortality and morbidity. In series published up to 1990, the mortality rate ranged from 14% to 44% ^{11) 12) 13) 14)}.

Following the development of diagnostic imaging and neurosurgical techniques, mortality rates fell, reaching rates of around 10% in most series published over the last two decades ^{15) 16)}.

Nonetheless, postoperative morbidity has continued to range from 18.9% to 77% ^{17) 18) 19)}.

Meticulously preserving venous sinuses is important since the risk of venous infarction cannot be predicted even with radiological good venous collaterization and apparent venous sinus blockade by tumor. Laterally situated tumors carry a better prognosis when compared to the medially situated ones. Leaving a small residual tumor in an effort to preserve important neurovascular structures does not obviate the expectation of a good long-term prognosis with minimal morbidity and low recurrence rates ²⁰⁾.

see Tentorial meningioma case series.

Tentorial meningioma case reports.

Signorelli, Francesco. (2013). Tentorial meningiomas by Thieme.