Early detection of asymptomatic phase or paraneoplastic manifestations in precancerous lesions and an early, correct and accurate diagnosis in terms of pathology of the lesion in question, makes important chances of healing and prolonged patient's life expectations. We present the case of a young patient who came to the emergency room and then admitted in the cardiology department with a heart rhythm disorder. The medical investigations that followed (gastric endoscopy, biopsy, histological and IHC exams), finds gastric polyps, which proved to be gastrointestinal stromal tumors (GIST).