Meningioma

Arise from arachnoidal cells

Well circumscribed, vascular tumors

Dural based 

Path: (all images from Dr.Pytel's CNS tumors lecture)

lobulated, "islands of cells" separated

whorls, relatively a-cellular/not dense in cells, with normal appearing cells that all look the same.

Pseudoinclusions, monomorphic ovoid cells. 

Subtypes of meningoma: 

Signs of poor prognosis/higher grade: 

- Tumor invading brain tissue 

- Proliferative activity (MIB-1) staining

- Lots of mitotic activity 

Prognosis: 

WHO grade I: recurrence 7-20%

WHO grade II (atypical): recurrence 29-40%

WHO grade III (anaplastic): recurrence 50-78%

Female predominance, esp in spine meningomas - 10:1 ratio