The clinical, laboratory and instrumental data of a patient with thrombotic thrombocytopenic purpura (TTP) are reported in detail, with reference to an articulated therapeutic regimen including plasma exchange, high-dose methylprednisolone and dipiridamole. Particular emphasis is placed on the dramatic improvement obtained with this treatment despite a very delayed diagnosis and prolonged, severe neurological involvement. A short discussion and review of the literature concerning the role of plasma-exchange in the treatment of TTP is reported.