Rare Case of Convexity Meningioma Growing into Arachnoid Cyst

• Published in: World neurosurgery 2018-09, Vol.117, p.199-202
• Main Authors: Schul, David B., Meier, Michael P., Földvari, Zsuzsanna, Krammer, Matthias J., Lumenta, Christianto B.
• Format: Article
• Language: English
• Subjects: Arachnoidal cyst; Atypical meningioma
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2018.06.040

Meningioma growing into an arachnoid cyst is an extremely rare event. Only 3 cases are reported in the literature. In 2 of them, an operative procedure in or near the arachnoid cyst preceded tumor growth. We report a case of a patient requiring marsupialization of an arachnoid cyst of the middle cranial fossa. On follow-up, 3 years postoperatively he showed no signs of recurrence or tumor growth. One year later, the fourth year after surgery on the cyst, he presented with large tumor growth into the former cyst's cavity. Pathologic workup after resection revealed an atypical meningioma (World Health Organization grade II). We discuss the possible pathogenesis in light of the scarce published literature, as well as the differential diagnosis of this rapidly growing tumor. •Meningioma growing into an arachnoid cyst is an extremely rare event; only 3 cases are reported in the literature.•In this case, a previously operated arachnoid cyst presented with a rapidly growing meningioma into an arachnoid cyst.•We discuss the possible pathogenesis in light of scarce published literature and the differential diagnosis.