Rethinking origins of pineal meningiomas

Abstract

Objective To investigate the clinical data and origin of pineal meningiomas, and to discuss the definite meaning of the term interpositum . Methods From January 2005 to December 2016, 21 cases of pineal region meningiomas underwent operations at Department of Neurosurgery, Nanfang Hospital, Southern Medical University and were enrolled into this retrospective study. Analysis was conducted on the clinical characteristics, imaging findings and surgical video data of those patients who were divided into 2 groups according to literature: falcotentorial meningioma group and velum interpositum meningioma group. Comparison was conducted between the 2 groups. Results Among 12 cases of falcotentorial meningiomas, 4 cases were originated from cerebral falx, 4 from cerebellar tentorium and 4 from straight sinus. Among 9 cases of velum interpositum meningiomas, 7 were originated from the cerebral arachnoidal envelope, 1 from the posterior cerebral vein and 1 from pineal surface. Postoperative pathological examination confirmed the diagnosis of meningioma in all cases. Among those, total resection was achieved in 16 cases and subtotal resection in 5. There were 3 cases of vertical movement limitation of the eyes, 7 cases of isotropic hemianopia, 1 case of hemiplegia, and 1 case of death. Conclusions The falcotentorial meningioma and primary pineal meningioma might be more appropriate for classification of origins of pineal meningiomas. The term interpositum may not be able to accurately reflect the origin of meningioma in the pineal gland region. During resection of pineal gland meningiomas, the protection of large veins and collateral circulation is of much significance. Key words: Meningioma; Pinealoma; Classification; Neurosurgical procedures