Tumors of the Meninges

Abstract

The first accounts of meningeal tumors were those of Louis [2023] and Cruveilhier [610], while the first distinction of “psammomas” from fibromas and dural sarcomas was made by Virchow [3556]. However, it was with Bailey [128] and Cushing [623, 626] that the nosography of meningiomas was outlined, as for many other tumors of the CNS. It is evident that both the terminology and the various classifications proposed reflected all the uncertainties regarding the tissue of origin of meningiomas [2974]. For many years, for example, the opinion that these tumors originated from endothelial “dural” cells prevailed, so that they were called “dural endotheliomas.” Cleland [530] commented on their possible origin from arachnoid cells which had remained included in the dura, an idea which was reaffirmed and sustained by Schmidt [3057] and by Cushing and Weed [630]. Though the origin of endotheliomatous meningioma from arachnoid residues in the zones of development of pacchionian granulations is today generally accepted, uncertainties still exist for the fibroblastic type [3708]. Many have attempted to clarify the last point. Mallory [2083] and Penfield [2603], on the basis of Ribberfs concept [2775], tried to demonstrate that the fibroblast is the typical cell composing a meningioma. They proposed the term “fibroblastoma.” On the other hand, other authors [2468, 2860, 2859], and in general the French school, sustained the neuroectodermal origin of the leptomeninges and of the neoplastic derivatives. Faced with these contrasting opinions, grounded mainly on embryogenetic criteria, classifications based on morphological and biological criteria became increasingly important.