Rosenthal fibers, birefringent gliofibrillary changes and intracellular homogenous conglomerates in tissue cultures of gliomas

The formation of Rosenthal fibers in gliomas grown in vitro is usually preceded by overproduction of fibrilles within fine, unusually elongated and muddled cellular processes, which form dense meshwork in the growth zone of cultures. Small-granular desintegration of these processes—or of entire cell bodies—and secondary condensation of are the next steps in the production of Rosenthal fibres, which as a rule do not show birefringency.The birefringent gliofibrillary changes develop by primary intracellular condensation of fibrilles which is not preceded by desintegration. The condensed fibrilles show birefringency both in early, longitudinal formations and in subsequently formed loops, tangles and balls.Both types of changes may be observed in the same cultures, although Rosenthal fibers develop mostly in cerebellar astrocytomas, whereas birefringent gliofibrillary changes are particularly frequent in immature, subependymal gliomas with signs of astroblastic or oligodendroglial differentiation. Both kinds of features are considered to be the results of failed metabolic hyperactivity of aberrantly differentiating cells of subependymal Anlage, in course of their pathological proliferation (dysplasia) and not as products of an ordinary degeneration, which seem to be the homegenous intracellular conglomerates, the third type of the described changes. The nature of cells which show fibrillary changes and the pathomechanism of these changes are discussed.