Tumors of the meninges: proposed modifications of the World Health Organization classification.

The present WHO classification of meningiomas has served us well. In keeping with the adage, "if it ain't broke, don't fix it," alterations should be made with due caution. These proposed modifications of the WHO classification are prompted by advances in our understanding of the pathobiology of meningeal neoplasms, as well as a need for an orderly scheme based upon factors of clinical importance. The author is well aware, that given the vastly differing technologies available to those utilizing the "blue book," its application must have a basis in routine histology rather than in "high-tech" procedures. No classification is ideal, but the modifications suggested represent a compromise between the pathologist's need for a complete morphologic exposition and the clinician's desire for a concise classification of therapeutic and prognostic significance.