Methods of Pathological Study

Abstract

The techniques of studying the pathological processes in the nervous system are only slightly different from those used in a general pathological department. Although in the latter the routine study is simple and generally limited to the application of a few methods, in neuropathology it is more diversified. A selective demonstration of the various components of the central nervous system, by using various staining methods, is often necessary. These demands make the course of investigation both longer and more difficult. In a way similar to general neuropathology, we investigate the tumor according to the principles of Spielmeyer—by site, manner of growth, and type. Our study of tumors includes not only the cell type—which, demonstrated by metallic impregnation techniques, was given altogether too much attention in the early contributions of Bailey—but the following as well: manner of growth and spread of the tumor cells; behavior toward the brain tissue (myelin sheath, axis cylinders, ganglion cells); the architecture formed by cell groupings as opposed to the form of individual cells; the degree of cellularity; the life-span of the individual cells; the formation of fibers; the behavior of the connective tissue (free and associated with blood vessels); regressive processes like necrosis, fatty degeneration, calcification, mucoid degeneration, etc. In order to classify a tumor, all of the foregoing points have to be taken into account, and only those tumors will be classified together that agree in a majority of these characteristics. Identical or similar cells alone—with differences in other characteristics—do not constitute a decisive criterion for the classification of a tumor.

For technique and staining methods, see the directions of Romeis, 1940; Schmorl; Spielmeyer, 1927; Masson, 1923; Russell, 1939; Anderson; etc.