Evolutive particularities of gastrointestinal stromal tumors (GISTs)

Abstract

Introduction: GISTs are the most common mesenchymal tumors specific to the GI tract, generally defined as KIT CD 117 and CD34 positive tumors with specific histological features. They derive from Cajal cells or their precursors, most commonly occur at the age >50 years in the stomach, small intestine, rectum and colon <10%, and less than 5% in esophagus, and can be malignant or benign. The symptomatology is non-specific, being diagnosed by the complications: hemorrhage, intestinal obstruction or perforation. Materials and methods: We have selected 10 cases of GIST hospitalized in the last four years with the same evolutionary feature: an acute complication that required emergency intervention. A positive diagnosis was established with postsurgical immunohistochemical tests, using antibodies antiCDl 17, CD34, Ki67 and vimentin. Results: GIST were recently defined as a separate histopathological entity and therefore, there is no standard protocol for its diagnosis and treatment. In 70% of cases the clinical signs are present the rest being asymptomatic discovered within a complication with intra/extra luminal bleeding, perforation or occlusion. Presurgical histopathological confirmation is not mandatory due to a high risk of dissemination and hemorrhages. Our 10 cases started with an acute complication that needed an emergency surgery: 8 with upper GI bleeding, 1 perforation, 1 occlusion. The diagnosis was established using immunohistopathological examination with antibodies anti C D 117, CD34, actin and vimentin. According to the mitotic index (Ki67+) and tum or size we have included them in Fletcher classification of malignancy evolution. The GIST evolution is inpredictable and requires an oncological monitoring of all patients. Conclusions: GISTs are part of intestinal mesenchymal tumors that can clinically evolve with a complication such as: occlusion, bleeding and perforation. The immunohistochemical test are necessary in order to establish a positive diagnosis and prognosis. The surgical act is the only treatment and followed by a long observation by oncologists.