Pathophysiology
1) tumor of arachnoid cells of meninges 2) usually attached to dura 3) may invade skull but rarely invades brain tissue 4) found most commonly along dorsal surface of spinal cord, along sagittal sinus, over cerebral convexities, and at the cerebellar-pontine angle
Signs and Symptoms
1) occasionally, is asymptomatic and found incidentally 2) symptoms are generally caused by mass effect 3) focal seizures 4) focal neurologic findings 5) increased intracranial pressure 6) loss of smell (if located in frontal lobes) 7) visual defects of optic neuropathy in one eye and hemianopia in the other if located anterior to chiasm
Characteristic Test Findings
Radiology – 1) well-circumscribed, intensely contrast-enhancing lesion on CT and MRI 2) “dural tail” of contrast streak may be seen on CT scan 3) commonly associated with hyperostosis of skull
Histology/Gross Pathology
1) arises from meningothelial cells of arachnoid 2) most tumors are in intimate contact with dura 3) well-circumscribed tumors with whorls of spindle cells and psammoma bodies
Associated Conditions
neurofibromatosis types 1 and 2
Inheritance/Epidemiology
1) second most common primary brain neoplasm after astrocytoma 2) uncommon in children 3) rarely can be overtly malignant
Treatment
1) resection for cure, if possible 2) if not easily approached surgically, local external beam radiation, or gamma-knife radiation is used 3) if small and asymptomatic in an elderly patient, it can be observed with serial CT scans, as tumors are very slow growing
Tips for USMLE
if brain tumor appears to be attached to the dura, think meningioma
Related Posts
