Artikel
Macrocystic meningiomas: the impact of cyst morphology and histological subtype for surgical decision-making
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Veröffentlicht: | 4. Juni 2012 |
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Gliederung
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Objective: Meningiomas with associated peri- or intratumoral cysts are an uncommon entity. Treatment of asymptomatic tumors and the necessity and feasibility of cyst wall resection are controversial. The present study summarizes our experience with microsurgical resections of these lesions and analyses potential factors significant for surgical decision-making.
Methods: A total of 28 consecutive patients operated on for cystic meningiomas from 1991 to 2011 were included in the study, representing the largest series reported so far. Neuroradiological features such as site of tumor growth, localization of cysts and enhancement of its walls were correlated to cyst contents and distinct histopathological characteristics like tumor subtype and cyst lining.
Results: The tumor localizations at the cerebral convexity and the falx were much more common than in meningiomas in general, and at least three cases were misdiagnosed as “cystic gliomas” prior to surgery. If the extratumoral cyst walls exhibited contrast-enhancement, they were always composed of tumor tissue. However, a lack of enhancement of the cyst wall did not preclude its neoplastic lining, although it was found to be built up of neuroepithelial tissue without tumor in most of these cases. At surgery even the true neoplastic cyst lining could not always be completely resected as some were ill-defined and/or enclosed by eloquent brain regions. Surprisingly, 32% of the tumors showed an atypical histological subtype (WHO grade 2). The WHO grade, however, could not be predicted by analysis of cyst-content or specific neuroimaging characteristics. With regard to patient age, atypical tumors occurred on average almost 10 years earlier than their benign counterparts.
Conclusions: Cystic meningiomas represent a distinct biological subtype, since atypia occurs by 6.5 times more often than in meningiomas in general. Therefore, surgical removal of these lesions should be advocated even in asymptomatic patients. If the cyst wall shows contrast enhancement on imaging, it should be removed at surgery due to its neoplastic properties whenever feasible.