ABSTRACT
Rosenthal fibers (RFs) are intraastrocytic hyaline inclusions that accumulate in a variety of pathological conditions. Initially described in the wall of a syringo myelic cavity over 100 years ago (1), RFs are now known to occur, most com monly, as a reaction to slowly expanding, often cystic lesions of the central ner vous system (CNS) (2). They typically occur, for example, in reactive astrocytes adjacent to craniopharyngiomas, pineal cysts, and syrinxes, and in neoplastic astrocytes of pilocytic astrocytoma. RFs may also occur in the gliotic reaction in and around vascular malformations, while uncommonly they may be encoun tered in chronic multiple sclerosis plaques and in reactive glial tissue in brains affected by fucosidosis (3,4).
