•Meningiomas arise from arachnoid cells.
•Their cause is not known but occasionally they arise
at sites of trauma or irradiation or in some
hereditary tumor diatheses such as neurofibromatosis.
•The tumor grows
from arachnoid cells when there has
been loss of tumor suppressor genes and activation of protooncogenes.
•Why these changes occur is not known.
•Meningiomas make up 15 - 20% of all
•They are more comman in women than men, probably related
to their tendency to have estrogen and progesterone
•They are the only truly benign tumor in that they
usually do not recur after complete surgical removal.
•Patients usually have
the slow onset of focal neurological
signs, occasionally with seizures.
•Complete removal of the tumor is usually curative.
|General Gross Description|
•Meningiomas have a smooth
bosselated external surface
which is usually pink-tan in color.
•Cut surface shows a firm, tan tumor mass with fasicles that tend to whorl
•These tumors may invade the dura but normally do not invade
the brain or show necrosis.
•The brain is compressed beneath the tumor.
|General Micro Description|
meningiomas are made up of plump
spindle or polygonal cells which in some areas tend to form lobules, in
others, fasicles of cells tend to
stream and form small whorls.
•Psammoma bodies (round calcifications) are often
present but mitoses and necrosis are uncommon.
• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp.1349-1350.
• Poirer J et.al. Manual of basic neuropathology. Philadelphia: Saunders, 1990, pp.36-40.