MRI in the diagnosis of cystic meningiomas: Surgical implications

Abstract

Nine cases of cystic meningioma diagnosed by MRI are described. All cases were surgically confirmed. The lesion was extra-axial with a clear dural attachment. On T1-weighted images the solid component was iso-hypo-intense in 6 cases and iso-hyperintense in 3; on T2-weighted images it was hyperintense in 7 cases, iso-intense in 2. After i.v. injection of gadolinium, the solid component enhanced in all cases and a "dural tail" were visible in 8 cases. No gadolinium enhancement of the cyst wall was observed in Nauta's types II and III. The authors found MRI to be very useful for diagnosis of cystic meningioma but insufficient for differential diagnosis between types II and III according to Nauta. This aspect requires further study, especially in view of the implications of this differentiation in terms of surgical management.

Peritumoral cystic meningioma: A report of two cases and review of the literature

“…Intratumoral cysts (Nauta types I and II) are likely to be caused by microcystic degeneration, ischemic necrosis or hemorrhage within the tumor (2,23,25). In addition, transudation or secretory changes within the meningioma may also lead to the formation of cysts (25); therefore, the cystic wall of intratumoral cysts (Nauta types I and Ⅱ) contains neoplastic cells and its immediate removal is required (3,26,27). The formation of peritumoral cysts (Nauta type III) may be due to reactive gliosis toward the meningioma or the evolution of cerebral edema to form peritumoral cystic cavities (22,23).…”

“…The mechanism underlying the formation of peritumoral cyst meningioma with neoplastic cells on the wall involves degeneration, necrosis, responsive glial proliferation, spreading of neoplastic cells in the fluid or a combination of these (11). MRI remains the optimal diagnostic means for the diagnosis of cystic meningioma, but it is not sufficient to determine the particular tumor type (27). Only microsurgical inspection and histological examination can lead to the final diagnosis of the type of cystic meningioma (27).…”

“…MRI remains the optimal diagnostic means for the diagnosis of cystic meningioma, but it is not sufficient to determine the particular tumor type (27). Only microsurgical inspection and histological examination can lead to the final diagnosis of the type of cystic meningioma (27). Combined MRI and diffusion-weighted imaging (DWI) may be efficient in diagnosing the type of cystic meningioma (4,33); however, as glioma was the initial diagnosis in the present study, DWI was not utilized.…”

“…Contrast-enhanced MRI may assist surgeons in determining whether neoplastic cells are present in the cystic wall; however, the wall could be enhanced despite the absence of tumor cells (34). Furthermore, biopsy was found to detect tumor cells on the cystic wall, even in cases where these were not detected by contrast-enhanced MRI (3,27). It is therefore not accurate to support the absence of tumor cells based merely on the negative results of contrast-enhanced MRI (20,27,35).…”

“…Furthermore, biopsy was found to detect tumor cells on the cystic wall, even in cases where these were not detected by contrast-enhanced MRI (3,27). It is therefore not accurate to support the absence of tumor cells based merely on the negative results of contrast-enhanced MRI (20,27,35).…”