New data on the ultrastructure of the corpus amylaceum (polyglucosan body).

During the semiquantitative evaluation of the occurrence of the corpus amylaceum (CA) in a large quantity of autopsy and biopsy material (1,407 cases), electromicroscopical (EM) and scanning EM examinations were carried out on 8 autopsied cases where CA was demonstrated. The EM examinations appeared to underline the astrocytic origin of the CA formation, which is initiated in the astrocytic fiber system by glycogen and other carbohydrate polymers. The biophysics of the development of the CA is indicative of the same mechanisms as for (mainly intracellular) inclusion bodies. The large amount of CA that develops at the predilection sites is a consequence of metabolic damage, a large quantity of cerebrospinal fluid and recurring disturbances in the barrier functions. The abundant CA may cause secondary blood-brain barrier disturbances. This working hypothesis demands further investigations and the continuation of research by modern immunocytochemical and ultrastructural methods recommended.