Rosenthal fibers in Alexander disease (infantile type) (photomicrograph)

This boy's first sign of developmental delay began after the first year. He had an enlarged head by 18 months and died at age 6 years. (A) In the cerebral cortex, Rosenthal fiber accumulations are evident in the characteristic subpial and perivascular sites, whereas elsewhere in the cortex only scattered Rosenthal fibers are seen. (B) The cerebral white matter contains diffuse and extensive deposits of Rosenthal fibers, as well as perivascular accumulations. Almost no myelin is present, which would normally stain darkly with this Luxol Fast blue. (x82 for A and B) (Reprinted with permission. Johnson AB. Alexander disease. In: Moser HW, editor. Neurodystrophies and neurolipidoses. Handbook of clinical neurology. Vol. 66, revised series vol. 22. Amsterdam: Elsevier, 1996:701-10.)