Suprasellar Meningioma Classification: Endoscopic Transnasal Perspective

Abstract

Objectives Midline suprasellar meningiomas include planum sphenoidale, tuberculum sellae, and diaphragma sellae meningiomas. Multiple classifications have been previously documented; however, they come with controversies and limitations, including those with surgical implications. The aim of this study was to classify suprasellar meningiomas based on their behavior toward the underlying bone and neurovascular structures. Methods Patients with newly diagnosed suprasellar meningiomas that underwent extended endoscopic transnasal approach between 2015 and 2021 were included in this study. The following parameters were evaluated: chiasmatic sulcus length, location of the optic chiasm and nerves, optic canal involvement, and vascular displacement. Results We identified 40 cases of midline suprasellar meningiomas, 1 diaphragma sellae meningioma (type A), 10 tuberculum sellae meningiomas (type B), 9 chiasmatic sulcus meningiomas (type C), and 10 planum sphenoidale meningiomas (type D). Asymmetrical visual complaints were most common in chiasmatic sulcus meningiomas, followed by tuberculum sellae meningiomas (66 and 50%, respectively). Chiasmatic sulcus meningiomas showed increased separation between the optic chiasm and the A1/A2 complex (8.9 mm) compared with tuberculum sellae (2.7 mm) and planum sphenoidale (1.9 mm) meningiomas. Compared with other types, increased chiasmatic sulcus length was observed in chiasmatic sulcus meningiomas. Conclusion Preoperative evaluation of bone involvement and tumor relation to neurovascular structures can be used to classify suprasellar meningiomas. Chiasmatic sulcus meningioma is a distinct subtype of suprasellar meningiomas. Its unique behavior toward nearby neurovascular structures could be of surgical value during tumor resection.

Keywords: chiasmatic sulcus; meningioma; suprasellar.

Fig. 1

Suprasellar anatomy. ( A ) Superolateral view of suprasellar area showing anatomical bony land marks. ( B ) Midsagittal diagrammatic illustration of the sella and suprasellar areas showing the bony landmark, the new classification of suprasellar meningioma, and the arachnoid layer medial lamina terminalis membrane. ( C ) CT midsagittal view of sella and suprasellar area showing the anatomical bony land mark. ( D ) A superior view of cadaveric dissection at suprasellar area identifying the arachnoid layer medial lamina terminalis membrane and its attachments with optic nerves and chiasm. CS: chiasmatic sulcus; Lt: left; MLTM: medial lamina terminalis membrane; ON: optic nerve; PS: planum sphenoidale; Rt: right; TS: tuberculum sella.

Fig. 2

( A ) Magnetic resonance imaging (MRI) T1 with contrast, sagittal view, demonstrates the displacement and separation of optic chiasm posteriorly ( yellow arrow ) and A1/A2 complex superiorly ( red arrow ). ( B ) MRI T1 with contrast images: coronal view demonstrates the displacement of both optic nerves lateral ( yellow arrows ). ( C ) CT sagittal view bone window showing the measurement method for sulcal length. ( D ) MRI T1 with contrast, coronal view and ( E ) MRI T1 with contrast, axial view, both demonstrating the extension of the tumor through optic canal ( blue arrows ) medial to the optic nerves ( yellow arrows ).

Fig. 3

Diagram and radiological illustration of suprasellar meningiomas subtypes: Type A diaphragma sellae meningioma: ( A ) diagram illustration of type A diaphragma sellae meningioma, ( B ) CT scan sagittal view showing the sulcal length, ( C ) MRI with contrast coronal view showing tumor extension in the optic canal inferior to the optic nerve ( blue arrow ), ( D ) MRI with contrast sagittal view showing the displacement of the neurovascular structure superiorly, optic chiasm ( yellow arrow ) and A1/A2 complex ( red arrow ). Type B tuberculum sellae meningioma: ( E ) diagram illustration of type B tuberculum sellae meningioma, ( F ) CT scan sagittal view showing the sulcal length, ( G ) MRI with contrast coronal view showing tumor extension in the optic canal medial to the optic nerve ( blue arrow ), ( H ) MRI with contrast sagittal view showing the displacement of the neurovascular structure posteriorly and superiorly, optic chiasm ( yellow arrow ) and A1/A2 complex ( red arrow ). Type C chiasmatic sulcus meningioma: ( I ) diagram illustration of type C chiasmatic sulcus meningioma, ( J ) CT scan sagittal view showing the sulcal length, ( K ) MRI with contrast coronal view showing tumor extension in the optic canal medial to the optic nerve ( blue arrow ), ( L ) MRI with contrast sagittal view showing the displacement and separation of the neurovascular structure posteriorly, optic chiasm ( yellow arrow ), and superiorly A1/A2 complex ( red arrow ). Type D planum sphenoidale meningioma: ( M ) diagram illustration of type D planum sphenoidale meningioma, ( N ) CT scan sagittal view showing the sulcal length, ( O ) MRI with contrast coronal view showing tumor extension in the optic canal superior and medial to the optic nerve ( blue arrow ), ( P ) MRI with contrast sagittal view showing the displacement of the neurovascular structure posteriorly, optic chiasm ( yellow arrow ) and A1/A2 complex ( red arrow ).

Fig. 4

Case demonstration of type C chiasmatic sulcus meningioma. ( A ) CT scan sagittal view of the sellar area showing the sulcal length. ( B ) MRI with contrast coronal view showing tumor extension to the left optic canal ( blue arrow ). (C) Sagittal MRI with contrast showing the displacement and the separation of neurovascular structure posteriorly, optic chiasm ( yellow arrow ) and superiorly A1/A2 complex ( red arrow ). ( D ) Intraoperative picture of the arachnoid layer (medial lamina terminalis membrane) after removing the tumor as it was resting over it and protecting the optic chiasm. ( E ) Intraoperative picture after removing the tumor showing the separation between the optic chiasm and A1/A2 complex.

Fig. 5

Case demonstration of type B tuberculum sellae meningioma. ( A ) CT scan sagittal view of the sellar area showing the sulcal length. ( B ) MRI with contrast coronal view showing tumor extension to the right optic canal ( blue arrow ). ( C ) Sagittal MRI with contrast showing the displacement of neurovascular structure posteriorly and superiorly, optic chiasm ( yellow arrow ) and A1/A2 complex ( red arrow ). ( D ) intraoperative picture of the arachnoid layer (medial lamina terminalis membrane) after removing the tumor as it was covering the tumor and protecting the neurovascular complex.

Fig. 6

Case demonstration of type D planum sphenoidale meningioma. ( A ) CT scan sagittal view of the sellar area showing the sulcal length. ( B ) MRI with contrast coronal view showing tumor extension to both optic canals ( blue arrow ). ( C ) Sagittal MRI with contrast showing the displacement neurovascular structure posteriorly, optic chiasm ( yellow arrow ) and A1/A2 complex ( red arrow ). ( D, E ) Intraoperative picture of the arachnoid layer (medial lamina terminalis membrane) after removing the tumor as it was resting over it and protecting the optic chiasm.