Gastrointestinal stromal tumors (GISTs) are rare tumors and can be a cause of gastrointestibnal bleeding, when other causes have already been excluded. This mesenchymal tumors can be diagnosed hardly, and they should be included in any differential diagnosis. Our case illustrates the difficulty of diagnosis and sometimes shows how non-invasive test can be few helpful. Surgery is very often indicated, and becomes therapeutic and diagnostic. GIST tumors are rare and surgical resection with curative intent is the treatment of choice.