Atypical computed tomography features of intracranial meningioma: radiological-pathological correlation in a series of 131 consecutive cases.

While most intracranial meningiomas have characteristic computed tomographic (CT) findings, a significant number produce atypical images that may lead to a spurious histopathological diagnosis. The authors reviewed 131 consecutive, previously untreated cases of meningioma, all confirmed pathologically. Nine cases (7%) were misdiagnosed initially as malignant lesions based on CT findings alone. Features such as irregular areas of nonenhancing mass and well defined regions of persistent low density were the reasons for misdiagnosis. Close correlation with pathological findings of tumor necrosis, hemorrhage, scarring, and cystic change was noted. An unexpectedly high incidence of necrosis in untreated meningioma is noteworthy.