Concomitant progressive supranuclear palsy and multiple system atrophy: more than a simple twist of fate?

Progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) are both rare neurodegenerative diseases. In the Queen Square Brain Bank, from 2001 to 2008, we received 120 cases of pathologically confirmed PSP and 36 of MSA, and one had concomitant PSP and MSA pathology. The clinical symptoms in this case were compatible with PSP and did not predict the dual pathology. The growing number of collective case reports, including the one reported here, might suggest an increased prevalence of concomitant PSP and MSA than what would be expected by chance.