Gastrointestinal stromal tumours are the most common mesenchimal tumours of the 
gastrointestinal tract. Diagnosis of these tumours is difficult to establish, 
because symptoms are vague and traditional diagnostic tests are not specific. 
Natural history remains poorly defined and many criteria have been correlated 
with prognosis; for instance, some authors have found that GIST localization 
influences clinical behavior, that has not been confirmed by other authors; 
actually, tumour size, mitotic rate and complete resection seem to be the main 
prognostic factors. Surgical resection is the treatment of choice, with little 
efficacy reported for irradiation, conventional cytotoxic agents or both. 
Nevertheless, imatinib mesylate has recently demonstrated significant activity 
and tolerability in the treatment of malignant unresectable or metastatic GIST. 
Three cases of GIST, complicated by intestinal bleeding and intestinal 
obstruction respectively, are presented and a review of the literature is made.