Gastro-intestinal stromal tumours (GIST) are primary mesenchymal tumours arising from the gastro-intestinal tract. They are uncommon visceral tumours, preferentially located in the stomach and small intestine. The present paper will discuss the clinical presentation of GIST in a 32-year-old female (Case 1) and in a 72-year-old female (Case 2). In both cases the tumour is located in the duodenum which appears to be a rather unusual location (4%) for GIST. This work will illustrate that duodenal GIST can occur in extreme presentations, diverging from vague complaints to directly life threatening symptoms.