RESUMO
BACKGROUND: Gastrointestinal stromal tumors (GISTs) are common mesenchymal neoplasms of the digestive tract and may occasionally arise within the abdomen without gastrointestinal tract connection. GISTs have recently attracted widespread interest because of the development of effective targeted molecular agents against it. While synchronous occurrence of a GIST with a tumor of different histogenesis was thought to be very rare, it is now apparent that they are more common than previously believed. PATIENTS AND METHODS: We report our experience with GISTs and also six cases of GIST coexisting with other primary neoplasms. Using immunohistochemistry and mutational analysis, a possible correlation was investigated. A review of the literature was also conducted. RESULTS: There were no significant differences in the immumohistochemical and molecular profile between single GISTs and GISTs coexisting with other tumors, nor was there any mutational correlation between GISTs and the coexistent tumors of different histogenesis regarding KIT and PDGFRA genes. CONCLUSION: Further molecular biology studies are required in order to investigate thoroughly the simultaneous development of tumors with different histotypes.