Planum Sphenoidale Meningioma

General Considerations

• As many as 10% of meningiomas
• Typically occur in women in 5^th and 6^th decades of life
• Occur at the anterior cranial base overlying the cribiform plate of the ethmoid bone, frontosphenoid suture and planum sphenoidale
• Meningiomas are extra-axial lesions that arise from arachnoid cells
• Patients with neurofibromatosis type 2 (NF-2) have a 50% chance of developing one or more meningiomas

Clinical Findings

• Often attain significant size before producing symptoms
• Changes in cognition and personality
• Headaches
• Visual disturbances, often more severe ion one eye but both are commonly involved
• Seizures

Imaging Findings

• CT
• CT is important for showing bony involvement which may be helpful in surgical planning
• On unenhanced studies. They are isodense to slightly hyperdense
• With contrast, they enhance intensely and homogeneously
• There may be extensive surrounding edema
• Adjacent brain is compressed but not invaded
  
  
• MRI
• They have variable signal intensity on T1 and T2-weighted images
• After gadolinium, they again enhance homogeneously and intensely
• More perilesional edema may be seen than on CT
• At their periphery, an enhancing tail to the dura may be seen
• Cystic meningiomas may exhibit intratumoral or peritumoral cysts

Differential Diagnosis

• Multiple meningiomas may resemble metastases

Treatment

• Surgical resection
• Radiation therapy

 Planum Sphenoidale Meningioma. Unenhanced axial CT of the base of the skull shows a hyperdense midline mass (white arrows) arising from the planum sphenoidale region. 

Meningiomas of the Tuberculum Sellae and Planum Sphenoidale: A Review of 83 Cases. JE Finn, LA Moun. Arch Ophthalmol. 1974;92(1):23-27