1985 Volume 25 Issue 6 Pages 479-483
The authors present an unusual case of meningioma with extensive histological vacuolization. A 47-year-old woman had an episode of generalized convulsion with loss of consciousness. A plain computerized tomography (CT) scan revealed a diffuse hypodense mass lesion in the right parietal region. The postcontrast scan showed a diffuse and homogeneous enhancement of the mass. Total removal of the tumor was performed. Microscopic examination demonstrated extensive vacuolization of most of the tumor cells with numerous small blood vessels, except for small meningothelial and angioblastic components. The authors experienced another case, in which the microscopic findings contained variable sized vacuoles and microcysts. The CT scan showed a well defined large mass with large and small cysts, and a low density area.
In general, cyst or necrotic hypodense areas are occasionally seen within meningioma by CT scans, but no diffusely hypodense meningioma has been reported except for three cases. This low density is due to extensive vacuolization, which bears histological resemblance to the subarachnoid space. The pathogenesis of the cyst formation in meningioma is still obscure. It is suggested that forming of the macroscopic cysts from the microscopic vacuoles appeared to mimic the developmental process of the subarachnoid space in the embryo.
