Lateral ventricular cystic meningioma: 2 rare case reports

Abstract

Cystic meningioma is an uncommon meningioma variant that is often difficult to distinguish from other intra-axial tumors, including necrotic gliomas. Cystic meningiomas located in the ventricle are particularly rare and may be misdiagnosed with other brain tumors, including ependymoma, choroid plexus papilloma and neurocytoma, due to its location. The present study discusses two cases of lateral ventricular meningiomas, which exhibited intratumoral or peritumoral cystic changes on magnetic resonance imaging scans. The two patients underwent surgical treatment and histological examination confirmed one case of metaplastic meningioma and the other case of psammomatous meningioma. The two patients were middle-aged females and had been misdiagnosed prior to surgery. Although this clinical entity is rare, the diagnosis of meningioma should be considered, particularly in middle-aged female patients.

Keywords: cystic meningioma; diagnosis; intraventricular meningioma; magnetic resonance imaging.

Figure 1

MRI scans revealed a 4.5×5.0×4.0 cm heterogeneously irregular mass in the trigone of the right lateral ventricle with slight peritumoral edema. (A–C) Noncontrast-enhanced MRI scans revealed that the solid portion of the tumor was hyperintense on T2WIs and T2-fluid attenuated inversion recovery images and hypointense on T1WIs. The cystic portion of the central tumor was hypointense on T1WIs and hyperintense on T2WIs. (D and E) Contrast-enhanced T1WIs revealed mild enhancement of the tumoral parenchyma following the injection of a contrast medium. Patchy calcification, which was revealed as hypointense in every sequence, was exhibited in the lateral marginal section of the tumor and scattered punctate calcification was also located within the solid area. (F) Microscopic examination of the resected tumor revealed that the left side was meningothelial cells and the right side was osseous tissue (hematoxylin and eosin staining; magnification, ×200). MRI, magnetic resonance imaging; WIs, weighted images.

Figure 2

MRI scans revealed a heterogeneously cystic-solid mass with a size of 4.8×5.0×5.5 cm in the right lateral ventricle without peritumoral edema. (A–D) Noncontrast-enhanced MRI scans revealed that the solid area of the tumor was isointense on T1WIs, diffusion WIs and on an apparent diffusion coefficient map, and iso- to hypointense on T2WIs. (E) The tumoral parenchyma and septum demonstrated evident enhancement following the injection of gadolinium contrast media. (F) Pathological examination revealed excessive psammoma body formation (hematoxylin and eosin staining; magnification, ×400). MRI, magnetic resonance imaging; WIs, weighted images.