Maturation and anaplasia in neuronal tumors of the peripheral nervous system; with observations on the glial-like tissues in the ganglioneuroblastoma.

Six cases of peripheral ganglioneuroblastoma are described and analyzed; in general these contained neuroblasts, mature ganglion cells and cells of intermediate degrees of maturity. Portions of the tumor resembled the glial tissues of the central nervous system, but this is spurious, no glial cells or fibers being present. Such tissues contained cells of intermediate maturity, immature axons which characteristically stain poorly with silver stains for axons, and a paucity of connective tissue fibers. These tumors exhibit a tendency for continued maturation with decreased malignancy, and for anaplastic change with increased malignancy. These opposing tendencies make it difficult to predict the outcome with complete certainty, except possibly in those cases in which maturation is complete. Schwann cells are present in those tissues which have matured to form neurons with axonal processes. The Schwann cells are probably reactive, not neoplastic. The presence of Schwann cells in such mature tissues is most readily explained on the assumption that Schwann cells are mesenchymal in character, and have been formed by differentiation of multipotential primitive reticular cells in response to the formation of axons by the maturing neurons.