Formation of "neo-cortex" in a congenital human teratoma.

A congenital human teratoma contained a neuroectodermal mass with architectonic features similar to those of the normal developing neo-cortex. Surrounding a central cavity, a germinal, an intermediate and a cortical zone were clearly distinguishable from innermost to outermost. Glial fibers coursed radially through the intermediate and cortical zones. In the "cortical plate" neuronal elements were oriented radially with an inside out gradient of differentiation. Mesothelial tissue covered the outer surfaces of the "cortex". Over limited sectors a gap in the integrity of the meso-glial barrier were associated with neuroglial ectopias. The following points are of neurobiologic importance: the information of the "miniature cerebral cortex" occurred in the absence of any influence of afferent subcortical fibers. The radial alignment of glial fibers between the germinal pseudostratified epithelium and the outer surface occurred only in sectors of the neuroectodermal mass where a "neo-cortex" was present, and may therefore have been a critical determinant in the formation of the "cortical plate". The integrity of the outer glial mesenchymal barrier may be necessary for the normal arrangement of cortical neurons.