Costello syndrome: report of six patients including one with an embryonal rhabdomyosarcoma.

Costello syndrome was first described in 1971. Besides papillomata, which were part of the initial description, patients tends to develop benign tumours of ectodermal origin. Aetiology is yet unknown but it is supposed to be the result of a sporadic dominant mutation. We report six patients with typical clinical findings and emphasise the importance of cardiac manifestations and the tendency to develop tumours. One patient developed an embryonal rhabdomyosarcoma, the occurrence of which has been reported twice before in patients with Costello syndrome.