CEREBRAL EDEMA IN INTRACRANIAL MENINGIOMAS - EVIDENCE FOR LOCAL AND DIFFUSE PATTERNS AND FACTORS ASSOCIATED WITH ITS OCCURRENCE

In a review of 68 meningiomas with good quality computed tomography (C T) scans, 40% had significant CT edema, in the sense of having low abs orption around tumor. Two distinct patterns of edema could be distingu ished. One was a diffuse white matter process appearing to represent a ctive transudation of water into white matter; this occurred in 43% of tumors with edema. The second, occurring in 57% of tumors with edema, was a localized peritumoral process. This distinction has important p athophysiologic and clinical implications. The diffuse pattern did not appear to reflect tumor size: it was found in 54.6% of tumors from 2 to 4 cm in diameter and 33% of tumors over 4 cm. It appeared more ofte n in tumors of the lateral sphenoid wing or subfrontal region and was more often associated with atypical and syncytial histological type, ( p < 0.05, two-tailed t test.). It occurred disproportionately often in atypical tumors and appeared to reflect some intrinsic property of th e tumor rather than compression of surrounding structures.