DIAPHRAGMA SELLAE MENINGIOMAS

DESPITE THEIR UNIQUE clinical, radiological, and surgical consideratio ns, diaphragma sellae meningiomas remain largely undistinguished from tuberculum sellae meningiomas. On the basis of our experience with 12 patients with diaphragma sellae meningiomas and our review of the lite rature, we classify these tumors into three groups: Type A, originatin g from the upper leaf of the diaphragma sellae anterior to the pituita ry stalk; Type B, originating from the upper leaf of the diaphragma se llae posterior to the pituitary stalk; and Type C, originating from th e inferior leaf of the diaphragma sellae. Each type has specific clini cal symptoms. Type A mainly presents with unilateral visual disturbanc es and visual field defects resembling those of tuberculum sellae meni ngiomas, although preoperative diabetes insipidus occurred in patients with large tumors. Type B causes fewer visual disturbances, but memor y disturbance and hypopituitarism occur. Type C closely resembles nonf unctioning pituitary adenomas; bitemporal hemianopsia and hypopituitar ism are common. Multiplanar magnetic resonance images can accurately d iagnose the tumor and establish its type. Surgical approaches include the cranio-orbital approach for Types A and B and the transcranial-tra nssphenoidal approach for Type C. Surgery is more difficult than for t uberculum sellae meningiomas because of the deep location and the diff iculty of dissecting Types A and B from the pituitary stalk. Repair of the sphenoid sinus to prevent cerebrospinal fluid leakage is mandator y for Type C tumors.