The study of Mathuranath et al 1 of corticobasal degeneration (CBD) and its overlap with frontotemporal dementia (FTD) contributes interesting information to a controversial area of neurodegeneration. Unfortunately it also introduces a potentially confusing histopathological diagnostic error. The authors found oligodendroglial inclusions which they considered to be glial cytoplasmic inclusions and claimed that these, diagnostic hallmark of multiple system atrophy, “have been described in other neurodegenerative diseases, including CBD”. This is clearly not the case.

To support their view the authors refer to two papers2 3reporting, among other cytoskeletal abnormalities, tau positive inclusions in oligodendroglial cells. A letter, published earlier in this Journal,4 but not quoted in the current paper,1 has also claimed that glial cytoplasmic inclusions are not exclusive to multiple system atrophy. The evidence …

Professor John Hodges