A light- and electron-microscopic study of a temporal-lobe ganglioglioma

Abstract

A temporal-lobe ganglioglioma was surgically removed from a 13-year-old boy who had psychomotor seizures for 4 years. By light microscopy, the ganglion cells were encompassed in a rich network of fibrous connective tissue. They merged with areas composed of sparser neuronal cells and numerous fibrillary astrocytes. The ganglionic and astrocytic areas contained many tiny eosinophilic granules, and proteinaceous globules which measured from 1 to 10 μ and often formed circular aggregates measuring up to 60 μ. By electron microscopy, three main cell types were seen: 1. (1) Ganglion cells, whose cytoplasm and processes frequently contained dense-core vesicles measuring from 1250 to 1800 Å. These cells were sometimes found in synaptic contact with adjacent processes. The dilated nerve cell processes often contained concentrically laminated bodies resembling those reported in experimental axonal reaction and degeneration. Some of these bodies may represent degenerative changes in the dense-core vesicles. Larger autophagic vacuoles, occasionally containing a dense-core vesicle, were also found. 2. (2) Glial cells with processes filled with filaments. The filaments sometimes merged with amorphous electron-dense material (Rosenthal fibers). In addition these cells contained many autophagic vacuoles, which were sometimes included within considerably larger membrane-bound profiles. On the basis of light microscopy both could represent protein inclusions. A number of neuroepithelial cells and processes could not be classified. 3. (3) A third cell type, probably mesenchymal, adjacent to abundant collagen fibrils and to convoluted basement-membrane material which often surrounded cell processes. The morphological features of this tumor are discussed in the context of the suggestion that central ganglion cell neoplasms may originate on a hamartomatous basis from ectopic autonomic neural tissue.