Resection of a 13-cm GIST from a 46-year old man that presented with abdominal pain. A. CT of the abdomen demonstrates a heterogeneous mass in the left abdomen. B. PET-CT demonstrating an FDG-avid mass in the left upper quadrant. C. Gross specimen following resection of the third and fourth portions of the duodenum and proximal jejunum where the tumor was arising. D. Pathology consistent with a GIST with strong KIT immunostaining. E. H&E staining demonstrating 23 mitoses (arrows) per 50 high power fields.