Risk assessment and pathological reporting of gastrointestinal stromal tumour

Gastrointestinal stromal tumour (GIST) is the most common mesenchymal neoplasm of the GI tract. GISTs form a biological continuum ranging from benign incidentally detected minute lesions (stromal tumourlets) of no clinical significance to large and highly malignant sarcomatous neoplasms. The disease is characterized by indistinct borders between biologically different subsets within its spectrum leading to unpredictable course of the disease in the majority of cases. Availability of effective tyrosine kinase inhibitors underlined the urgent need for a reliable risk assessment system to reliably identify those patients who are at a significant risk for disease relapse and would thus profit from currently available effective targeted molecular therapy. While several risk systems have been established for GIST over the last decade, evidence is growing that no single system is optimal for all patients. Accordingly, an individualized risk system integrating classical parameters (site, size, mitotic index), status of serosal mechanical barrier covering the tumour (presence of tumour rupture or serosal penetration) as well as several other still debatable histological (coagulative necrosis, venous invasion, mucosal infiltration), biomarkers (proliferative index, p16 expression, etc.), and molecular (specific mutation types, adverse chromosomal aberrations, etc.) prognosticators would be of superb value for selecting the most appropriate patient treatment.