[Gastrointestinal stromal tumors: a broad clinical spectrum from incidental -discovery to acute gastrointestinal bleeding].

Three cases of gastrointestinal stromal tumors (GIST) are reported as typical examples of the broad clinical spectrum in which these rare tumors can be detected. The first case describes an 82-year-old patient with a hemorrhagic shock due to upper gastrointestinal bleeding from a GIST of the stomach. GIST most frequently present with either gastrointestinal bleeding, abdominal pain or a detectable mass on physical examination or by ultrasound imaging. Clinically asymptomatic tumor growth also occurs as demonstrated by the second case of a 44-year-old -woman with an incidental finding of GIST during surgery of the esophagus. The cases are used to discuss the consequences for therapy and prognosis resulting from the heterogeneity of this tumor entity; the relevant immunohistochemical markers used to distinguish between various tumor subtypes of gastrointestinal mesenchymal tumors (GIMT) are listed. Since gastrointestinal stromal tumors (GIST) represent the most common subgroup of GIMT, we focus on the clinicopathological prognostic factors of GIST. The third case of a 40-year-old patient with a malignant GIST recurrence after surgery and exhibiting secondary resistance after one year of successful therapy with the receptor tyrosine kinase inhibitor imatinib (Gleevec), antagonizing pathogenetically relevant constitutive c-KIT activation, illustrates the potential and limitations of the only effective drug treatment for advanced GIST.