Biological Behavior and Grading (Prognosis)

Abstract

The following chapter will deal with the prognosis of the patients with an intracranial tumor. It had to be based on both the morphology and the corresponding biological behavior of the particular tumor. The classification of tumors has already been discussed, and it is clear that their biological behavior has to be defined by morphological characteristics of the tumor tissue and its clinical consequences. This kind of discussion started in general pathology long ago with the problem of the “malignancy of cancer” (von Hansemann 1898, 1920). Malignancy was ascertained in a tumor if anaplasia (von Hanse-mann) was observed. Anaplasia was defined for this author by the low grade of differentiation of a cell in comparison with the mother cell, and this dedifferentiation together with a higher capacity to metastasize caused a reduced survival capacity to live. The morphological phenomenon of anaplasia has now to be more broadly described with reference to discussions over the last century.