Gastrointestinal stromal tumors of the anorectum — A special entity: GISTs of the anorectum

Objective Until recently gastrointestinal stromal tumor (GIST) has been separated from other mesenchymal neoplasms and categorized as a special entity. Morphology of tumor cells and immunohistochemical findings with CD117 are crucial in the pathological diagnosis of GISTs. Newly developed drug imatinib mesylate (formerly called STI571) has been proved effective for GISTs. The distinction of GISTs and other mesenchymal tumors has great clinical significance, especially for lesions located in the anorectum.