[Pathogenesis of syringomyelia]

The absence of an ependimic layer in cases of syringomyelia described in literature and in the author's own studies, the dislocation of cavities on the background of formted gray matter, the structure of the edge of the cavity, as well as sclerosis, a gyalinosis of vessels and fibrosis of the meninx--all these phenomena confirm the opinion of syringomyelitic cavities as an acquired defect and not dysraphia. A comparative study of the morphogenesis of medullar cavities in inflammatory, vascular, traumatical processes and in syringomyelia permits to mark their histological similarity and postnecrotic genesis. The glyosis in syringomyelitic cavities has a different character. The fibrillar glyosis along the edge of the cavities appears due to reparative changes and plays a delineating role. Irritative glyosis appears more frequently in angiomatosis, accompanied by chronic microhemorrhages. Expressed glyosis with a formation of cellular rosettes is to a certain extent a tumor (astrocytomaa, epeudimoma), while a syringomyelitic cavity--a histiolytic cyst of a tumor.