Meningiomas Originated at the Falcotentorial Region: Analysis of Topographic and Diagnostic Features Guiding an Optimal Surgical Planning.

Background: Meningiomas arising at the pineal region are a rare entity and still represent a great neurosurgical challenge given their deep location and critical neuroanatomic relationships. The optimal surgical approach to treat these lesions is still under debate. Our objective is to review the topographic and diagnostic features of these lesions, which can help to guide an optimal surgical outcome.

Methods: We present 2 clinical cases of falcotentorial meningiomas successfully treated at our institution (2016-2017) with different surgical approaches. A literature review is performed, and a description of the classification, anatomic relationships, clinical features, diagnosis, and different surgical options and outcomes of these lesions is presented.

Results: The first patient was treated via a supracerebellar infratentorial approach, and the second patient was treated via a parieto-occipital interhemispheric approach. In both tumors, a gross total resection was achieved with no permanent neurologic deficits. In the literature review, gross total resection rates range from 33% to 100%, with no differences regarding the type of meningioma or the surgical approach performed. Permanent neurologic morbidity varies from 0% to 50%, and mortality rates range from 0% to 23%. The distortion and displacement of the vein of Galen and straight sinus represent the most important feature in the decision of optimal surgical approach.

Conclusions: Pineal region meningiomas represent very infrequent, challenging lesions, and their description in the literature is scarce. The systematic topographic classification of these tumors and evaluation of the neuroanatomic structures involved are crucial to guide a safe and optimal surgical approach and achieve satisfactory outcomes.