An explanation for the rarity of extraaxial metastases in brain tumors.


Primary brain tumors invade and metastasize within the central nervous system (CNS), but rarely extraaxially. A model explaining this behavior is presented. In non-CNS tumors metastases occur since subpopulations of cells capable of invasion and metastases are selected by the tissular environment, and in particular by the connective stroma, which opposes… (More)