Morphological Problems of Brain Tumors with Mixed Cell Population

Abstract

The present classifications of tumors of the glioma group ara based, like those of neoplasms elsewhere in the body, on the recognition of the morphological characteristics of the prevalent cell component. The existence has, however, long been recognized, in many cases, of a diversity in cell population which cannot reasonably be explained by a process of anaplastic degradation of the more differentiated glial elements. This discussion will be concerned with three different, and unrelated, aspects of this problem. The first is presented by tumors composed of more than one gliogenous element, often of adult form, and in which it cannot be argued that any one cell type is derived from another (mixed gliomas). The second bears on the rare group of ganglion-cell tumors of the central nervous system, in which both neuronal and glial elements can be demonstrated to participate in the neoplastic process (gangliogliomas). The third aspect concerns those composite tumors in which, by analogy with the “carcinosarcomas” found elsewhere in the body, a mixture of both sarcomatous and gliomatous elements are found in contiguity (mixed gliomas and sarcomas).