Cause:Neoplasia; chromosome 22q deletions and thereby assoc w neurofibromatosis type 2
Pathophys:Most commonly over hemisphere convexities; also deep in cleft (parasagittal), over sphenoid ridge, olfactory groove, spinal cord. Slow growing with few si's of brain damage. Often have estrogen and progesterone receptors. 2% are malignant
Peak incidence between age 50-70 yr; rare <20; 20% of all brain tumors, 25% of all cord tumors. Increased in irradiated children (Nejm 1988;319:1033), and patients with breast cancer. Female/male: 2:1
Very slowly progressive. After resections, 10-20% recurrence at 10 yr if thought to have been completely resected, 80% if obviously could not get all
Lab:Path:Uniform size cell whorls; these may calcify to form psammoma bodies
Xray:
Skulls show hyperostosis or radiolucency of underlying bone, large feeding vessel impression, foramen spinosum enlarged due to middle meningeal enlargement, 33% are calcified (Fraser, Edinburgh 1968)
CT scan usually is diagnostic; often do not show up on MRI unless gadolinium-enhanced