Meningioma of the pineal region: a surgical series of 10 cases

Abstract

Ten cases of meningioma of the pineal region were histologically verified at a single institution during an 8-year period. These represented 0.3% of 3061 intracranial meningiomas, as well as 6.2% of 164 pineal tumors. Patients were predominantly women. Symptoms and signs of increased intracranial pressure were most common, whereas Parinaud's syndrome was observed in only one case. Computerized tomography (CT) was the main diagnostic test used in the present series. It usually revealed a hyperdense mass with high-intensity contrast enhancement and a calcified mass eccentrically located at the periphery, which returned to its central location postsurgically and was likely to represent a calcified pineal gland. Magnetic resonance imaging was performed in the more recent cases and confirmed the suspicion raised by CT of a meningioma with a calcified mass at its periphery. Surgery was performed using an occipital transtentorial microsurgical approach with the patient placed in the semisitting position. Gross-total tumor removal was achieved in all cases, although this required sacrifice of the vein of Galen in six patients. Venous occlusion was performed only after adequate intraoperative verification of functional occlusion and blood flow diversion from the galenic system and had no consequences in any case but one. This latter patient had an infiltrative meningioma that was removed at the expense of intraoperative sacrifice of the two internal cerebral veins, as well as unavoidable trauma to the region of the quadrigeminal plate. All the remaining patients improved postsurgery, and only one had a permanent visual field deficit as a result of the surgical approach. Pineal meningiomas represent a rare subgroup of pineal tumors that can be treated surgically with reasonably good results. Sacrifice of major basal veins may be required to achieve radical tumor removal and can be tolerated by the patient provided that functional occlusion of the galenic system, as indicated by preoperative angiography, is verified during surgery.

Meningiomas of pineal region in children

“…The CT imagings features of germinomas, pineocytomas e even malignat tumors are very similar to the meningiomas 18,19 . Meningiomas of the pineal region, like many other tumors, present on the CT as a round mild hyperdense lesion, with homogeneous contrast enhancement 20,21 . Lack of surrounding oedema and tentorial attachment are common features of meningiomas of the pineal region 22 .…”

“…The presence of calcifi cation varies and depends on the type of tumor. Calcifi cation in meningiomas is relatively higher in children than in adults, but the incidence of calcification in pineal region tumors, particularly in pineal parenquima tumors and germinomas are high 20,23 . Finally, it is usually not possible to make a preoperative diagnosis of a specifi c histological variety of tumour based on CT characteristics alone.…”

Three-dimensional Computed Tomography Angiography of the Galenic System for the Occipital Transtentorial Approach

“…2,4,7,18,29,37,43,50) The greatest advantage of the occipital transtentorial approach over Stein's approach is the excellent operative view both above and below the tentorial notch, especially for removal of large tumors with extension in the superior, lateral (to the thalamus), and posterior-inferior (to the midbrain) directions or tumors that involve the deep venous system. 3,7,16,17,20,31,44,50) However, the vein of Galen, the basal vein ipsilateral to the approach, and the internal cerebral vein (ICV) may obstruct tumor removal 24,31,33,36) ; the superior sagittal sinus and the falx obstruct any approach from the midline trajectory, so tumors extending to the opposite side or anterior third ventricle cannot be easily reached 24,31,33,36,44) ; and visualization of the contralateral quadrigeminal region and ipsilateral lateral wall of the third ventricle is poor. 46) Therefore, the occipital transtentorial approach may cause hemorrhagic infarction resulting from obstruction of the great vein of Galen and its tributaries, 32,46) over-retraction of the occipital lobes, and Y.…”

“…44) However, occlusion of the great vein of Galen and the straight sinus cannot be avoided in many cases of meningioma, 1,12,17,30,34,45) although adequate collateral venous channels have usually already developed. 16) Such considerations emphasize that preoperative detailed evaluation of the venous system is very important.…”

Pineal Region Tumors

“…In a cohort of ten patients operated for a meningioma of the pineal region in all but one case there was no local recurrence at 3-year follow-up (Konovalov et al, 1996). There is still no general consensus for the treatment of gliomas of the pineal region.…”