Turcot's syndrome, clinically characterized by the coincident occurrence of 
primary tumors of the colon and the central nervous system, can genetically be 
divided into two syndromes: familial adenomatous polyposis (FAP) and hereditary 
nonpolyposis colon carcinoma (HNPCC). In the present case, a 60-year-old patient 
with glioblastoma multiforme and a history of hereditary malignomas is described 
as an example of a HNPCC-associated Turcot's syndrome. New molecular biological 
methods and results give deeper insight into clinical syndromes, and the better 
understanding improves diagnostics, therapy, and outcome estimations, even in 
rare diseases. In the present case, a new germinal mutation could be identified.