Reclassification of gastrointestinal mesenchymal tumors.

Background: Gastrointestinal stromal tumors - commonly called GISTs - are rare; yet, they represent an important type of mensenchymal tumors arising within the gastrointestinal tract. The acronym GIST was introduced in 1998 to define a well established pathological entity which bears a highly specific marker called KIT (CD117). Scientific interest for these tumors in recent years is mainly due to the progress in identification by immunohistochemistry and the advent of targeted molecular therapy.