Meningiomas with Unusual Intra-Extracranial Extension: Ectopic Entities?

Abstract

We describe two patients with meningiomas atypically appearing as long-standing forehead and vertex lumps. In both cases, CT scan and MRI identified large neoplasms arising in the frontal and parietal regions respectively with extra-cranial extension through the destroyed calvarium and intracranial development. At surgery in the first case the tumour was found adherent to the external dural layer without involvement of the internal layer thus falling into the ectopic class of meningiomas. In the second case, the dura appeared completely infiltrated by the neoplasm. Histological examination did not reveal any malignancy in either patient. Consequently, osteolysis was no of prognostic value. The role of neuroimaging is discussed, the relevant literature on extracranially protruding meningiomas is reviewed, and the clinical-surgical outcome is described.