[Turcot syndrome].

Turcot syndrome is the association of colorectal polyposis with primary neuroepithelial tumors of the central nervous system such as glioblastoma and medulloblastoma. Including putative patients, more than 150 familial or sporadic cases of the syndrome have been reported in literature. Since early reports, there is considerable controversy regarding the modality of genetic transmission and the distinction from other syndromes like familial adenomatous polyposis(FAP). Recent molecular evidence suggests that Turcot syndrome could be divided into the following two entities based on the distinct genetic backgrounds. (1) True Turcot syndrome(autosomal recessive): Intestinal polyps are less in number(< 100), large in size and apt to transform to the malignant tumor. Brain tumor is mainly diagnosed as glioblastoma or astrocytoma and mismatch repair genes might be involved. (2) FAP-associated type(autosomal dominant): Predisposing to medulloblastoma.