Intracranial Osteolytic Malignant Meningiomas Appearing as Extracranial Soft-Tissue Masses

Abstract

Malignancy is rare in intracranial meningiomas. Although the topic is widely discussed, there is little agreement in the literature as to the histological and radiological features that warrant the diagnosis of malignant meningioma. Three patients are described who had soft-tissue masses and underlying osteolytic lesions on computed tomography. All three patients also had a large intracranial component that proved to be a malignant meningioma. Rarely do meningiomas have all three of these features. We propose that a meningioma causing osteolysis and soft-tissue extension should be considered malignant until proven otherwise.

Osteolytic and Osteoblastic Lesion of the Skull in a Patient with Known Cancer History: A Typical Location of Meningioma

“…Although they are benign lesions, recent studies emphasize that intraosseous meningiomas have a higher incidence of malignant characteristics compared to intradural meningiomas [5,6]. The typical findings were found to be compatible with a meningothelial meningioma in our case.…”

Two Cases of Primary Osteolytic Intraosseous Meningioma of the Skull Metastasizing to Whole Skull and the Spine

“…Recent studies indicate that intraosseous meningiomas have a higher incidence of malignant features than intradural meningiomas have7,14,17). One report reviewed 65 published cases of intraosseous meningioma, assessed during the CT era, and found that 17 (26%) had atypical or malignant histological features10).…”

Giant Meningioma of the Cranial Vertex. Case Report.

“…Meningiomas causing osteolysis and soft-tissue extension should be considered malignant. 14) We treated our patient with fractionated radiotherapy. The long-term outcome in such cases is unclear.…”